I used to keep fishes since I was young, with ~15 years of pause in-between, when I attended high school and university. Back then, it was relatively low tech, with a filtration system done with an air pump and a sponge, actually. Now the situation is way better, but also requires more knowledge, as there are tons of products to choose from.

When I moved to Temeswar, due to work, I bought again a 40L aquarium Aquastart 340L and I've kept it until this year, when I wanted to have a bigger one in the new apartment: I said, let's make this one a high tech aquarium, and let’s see how it works, not necessarily being the main focus on keeping the costs down. So I started to study the forums regarding what's really the best equipment, soil, lighting, conditioner liquids, etc. when setting up a new aquarium. Now it's really easy and complicated in the same time, as there are lots of filters, lights, soil types, plants and fishes, compared to what was available when I was a kid. Then the idea came to write this instructable, as most of the time, the information is scattered and hard to find all together what's useful information.

Step 1: Chosing the Tank

Aquariums come in various shapes and sizes. Depending on the available space, one might be a better fit in your location than another. Size does matter, the bigger the better, not only because you can keep more species, but also because maintaining a bigger tank is easier than a smaller one.

When choosing a tank, usually, it's not advised to go under 40L, as it will be very hard to keep the biological balance in it. The bigger, the easier to maintain, but it also takes up more space.

As I had space only in the corner, I chose the Juwel Trigon 190L aquarium:
https://www.juwel-aquarium.de/Produkte/Aquarien/T...

Juwel is an old brand with good reputation, and they sell also accessories and replacement parts for their tanks and filters.

I had luck, as somebody was selling it 100kms away from me for about 100Euros, as he built a 400L one and had no space. The only thing, the lights were not supplied, so I had to buy new ones.

Such aquariums, as new, costs close to 500-600E, so it was really a bargain.

Step 2: Lighting

After the aquarium, the lighting is very important, as it influences the growth of the plants and the algae. Traditional lighting was done with PL-L fluorescent tubes, and you had an ON/OFF timer that controlled the lights. Usually 8-10 hours of lights per day should be sufficient for plants to grow well, and also to prevent excessive formation of algae.

Now the old tubes can be exchanged with LED tubes, but also panel-shaped LED lighting solutions are mode preferable, as you can control the brightness of the RGBW channels individually with PWM.

As Juwel had developed a relatively new and modern light system, I gave it a try:

https://www.juwel-aquarium.de/en/Products/Lighting/LED/HeliaLux-LED/HeliaLux-Spectrum/

It's expensive, but it was designed to fit on the top cover of the aquarium, and has IP68 water insulation, and it has good heat dissipation.

As I've learned, this is a much economical lighting system on the long run, as plants don't always need the whole spectrum.

I've ordered the light system from amazon, but didn't really read the description that the smart control device has to be bought separately for an additional 100E fee.

https://www.juwel-aquarium.de/Produkte/Beleuchtung/LED-Beleuchtung/HeliaLux/HeliaLux-SmartControl/

But for this lighting, it's really a must to be able to control the individual channels automatically.

Now I've setup something like in the picture, based on documentation about what are the plant needs regarding the light spectrum.

This module is done nicely, you have a web based interface where you can define up to 8 profiles, and for each profile you can define some thresholds and in-between it will fade automatically. Some people gave bad reviews, as it was hard to setup. It indeed requires some basic network-knowledge, but it runs independent of any cloud! And this is great. It has his own web-server that you can access by knowing the local IP address.

Regarding setup:

For example: at 6:00 AM the white channel starts to rise and at 12:00 the White channel is at maximum. In-between it will gradually fade. You can do this with each channel and you can define many set-points across the day. This way you can define a precise control over the lights.

After 2-3 month of usage, I would say not only it looks nice (for example, in the evening it will switch to a blueish faded light which simulates the moonlight) but also the plants are growing nicely. But actually, you don't need to buy this light system to have similar features, I saw in china lots of panels for aquariums much cheaper. Some of them already have some kind of manual control of the lights, but you can easily implement an automatic control by using one of these:

https://tasmota.github.io/docs/devices/MagicHome-with-ESP8285/

These controllers can be bought for under 10$ from Ali express or Bangood. But I saw them for sale also on local websites.

They are built with Expressif chips and you can flash the versatile tasmota FW on them and integrate it in any smart home system, as it has MQTT, for example. This is for advanced users, but some might have the skills and patience to do it.

But enough about the lights.

Step 3: Filtration

There are several types of filtration systems, varying from quite basic ones - a pump and a sponge - to multi-layered filters.

They can be internal ones, that sit below the water level, external ones, that are completely out of the tank, and the pump circulates the water out and in the tank through the filter mediums, or semi-external ones, these usually are located above water level, but below the hood of the tank (typically found in compact aquariums).

Depending on the filtration medium, this can consist of several sponges (that are doing the mechanical filtration), one recipient for the ceramic rings – that are needed for the growth of the bacteria, active carbon filters, etc.

Usually the more layers the filter has, the better the filtration is.

There is a debate regarding which filter is better: internal or external one. Some say the internal one is better, as water will always stay inside the tank, and it's more safer to run. With an external filter, the pump will pump out the water from the tank into the external filter and back in. If the hoses get damaged, the pump will pump out the water out of the tank, filling your home with water. That would be not so desired. So, one might think, internal filters are better, but it's not always the case. External filters can have higher filtration capacity, don't take up precious space inside the tank and are easier to clean.

Step 4: Soil Types

I've read a lot about soil types and why are they important for the plants. In a nutshell, there are active and passive soils. The active soils contain some nutrients and bacteria that is necessary to jump-start an aquarium. Passive regular soils are cheaper, but do not have these nutrients.

According to what they say on several forums, these 2 are well known and good quality:

https://www.aquasabi.de/ADA-Aqua-Soil-Amazonia

https://www.jbl.de/en/products/detail/3398/jbl-manado?country=us

I've used Amazonia in mine. Now if you're planning to keep an aquarium full of plants, it's advised to have around 4cm thick soil, so you an easily plant the roots in it , and the sanitary fishes won't be able to dig them up. This soil is usually mud-like, and doesn't need rinsing. So you just take it out of the bag in put it in the bottom of the aquarium. Now, you can leave it like this, but it's better to have a thin layer of some kind of stone gravel on it, as it will keep the water clean, preventing the fishes to dig up this soil.

I've used this one:

https://aquatic-nature.be/product/fresh-water/dekoline-quartz-de-en/dekoline-nero/

But anything that's volcanic or some hard stone will do. What's important is not to put in some kind of calcium-based gravel, as it will slowly dissolve and pollute the water. Also it will raise the PH of the water.

Some might prefer a more colorful gravel, but I kept it black, as it has a more natural look.

Step 5: Heating

Depending on what geographical region you're living in, during winter time it could be that you need to heat up the aquarium's water temperature to be suitable for tropical fishes.

Although there are some fishes that can happily live in 20-22C , most of the tropical fishes prefer a slightly higher temperature, somewhere in the 25-27C range.

To achieve this temperature, you will have to fit your aquarium with a heater.

There are several brands and of various wattage.

General rule: You should consider 1W per liter. That is, in case you have an aquarium of 100L, then an 100W heater is needed. For bigger tanks, a bigger heater must be installed.

This rule applies in case you keep the tank inside the house where you live as well. In case the house is not heated, then a higher capacity might be needed. Note that such a heater is capable of heating up maximum 8-9C from the starting temperature.

Example: If you have 20C in your home, then it's safe to set it to 27C, but in case you leave your home for the winter holidays, and you set the target temperature to 15C, then the heater will not be able to maintain the desired 27C set-temperature. In this case, a heater with a higher capacity might be needed.

Step 6: Air Pumps and Diffusors

Oxygen is also a necessary component in the ecosystem of the aquarium. Water can be oxigenated in many ways, like adding a diffusor for the filtration pump, that will suck in and spread air inside the aquarium:

https://www.juwel-aquarium.co.uk/Products/Filterin...

Another way to facilitate the oxigenation of the tank is to let the water "fall in" back to the tank from the filtration system. This is only possible with certain external filters or semi-external filters.

If none of the 2 solutions are possible, then adding an additional air pump and air stones will do the job, but this means additional power consumption and costs.

Back in the "old" days, air pumps were noisy and very loud, now, due to the damping systems they are very quiet.

One good brand is Tetra's APS pump lines:

https://www.tetra.net/en-gb/products/tetra-aps-aqu...

These are available in many sizes and white and black colour as well, and are known to be very silent.

Step 7: Starting the Aquarium

An aquarium shall be cycled before it's ready for accepting living life (fishes). A general mistake for beginners is that they populate the tank too early. This is one of the biggest mistakes one can do and it will inevitably lead to lot of dead fishes. In order to have a balanced environment suitable for fishes, there has to be a biological balance in the aquarium that should be able to sustain itself and regenerate on its own.

So, in order to have a healthy environment, the necessary steps that must be followed when starting a new aquarium are the following:

1) First you put in the soil. Like it was said before, a minimum of 4cm thickness must be assured, in order to be able to have the root of the plants well fitted. The thicker, the better as it will leave more space to the roots.

2) Fill it with water, only 10-20% and you put in most of the the plants. In the back it's good to choose taller ones, and in the front it's preferable to have the smaller ones, but it's up to each other's taste.

3) When the plants are in, you can put other stones and wood decorations in it. I've put in mine wood, but now I kind of regret it, maybe some stones would have been better. The wood did not want to stay on the bottom of the tank, I had to tie some ceramic plates to the bottom of it so that it's staying under water. Also, they say that after a couple of year, the wood will eventually start to rot and will have to be changed. Also, when you don't buy it ready-made from a store, it’s not advised to put it in the tank, unless you boil out the tannin of it. Also, it's good to collect some roots from a lake, as otherwise it will float. Some people put in the roots inside the water tank of the toilet for a couple of weeks, as when you flush, it will clear the water and fill it with fresh one, gradually getting rid of the tannin. If you don't do this, it will turn the color of the aquarium's water into a brownish color.

4) After the decoration is done, you can fill it up with tap water, and start the filtration pump together with the lighting system. Always keep the filtration pump on!

Now this is the tricky point. Lots of people populate the aquarium with fishes after 2-3 days, as the water test showed all parameters to be good.

BTW, I’m using this water test, but any other will do:

https://www.sera.de/en/product/pond/sera-quick-test/

This is one of the biggest mistakes one can do and it will inevitably lead to lots of dead fishes, frustration and in the end you will give up on this beautiful hobby.

In order to have a balanced environment suitable for fishes, there has to be a biological balance in the aquarium that should be able to self-regenerate.

The faeces of the fishes contain ammonia that is a toxic substance in high quantities that has to be broken down by bacteria into NO2 and NO3 (nitrates and nitrites). These must be further broken down into other substances.

Now in a new aquarium there are no such bacteria, therefore there if you put in the fishes right from the beginning, after a while the water gets toxic to them and they will die.

So what can you do to get these bacteria? There are several ways:

- You can buy some starter liquids that you will gradually add to the water, that contains these bacteria cultures. In a couple of weeks, they will multiply and you will have them in enough quantity to sustain a few fishes. There are several aquarium starter liquids, one might be this:

https://www.easylife.eu/products/freshwater/water-...

- You can add water from an already running aquarium that contains these bacteria

- You can use an existing sponge from an old, running filtration system. These bacteria live everywhere in the water, but are more concentrated inside the filtration system, mostly on the ceramic rings that are a must have, by the way, inside the filtration system.

- Periodically a small amount of food must be added, this will accelerate the growth of the bacteria as well. Keep in mind that overfeeding will deteriorate the water quality quickly, so a balance must be kept.

Of course, you can combine the methods from above, which will lead to an accelerated growth of the bacteria, but even so, it's mandatory to let it run without fishes for at least 3 weeks before putting in the first occupants.

Also, if you have plants in the aquarium, it will help things to stabilize faster, as plants are also consuming nitrates and nitrites, but you must be aware that plant leaves die and start to rot eventually. These must be collected as well manually, or eaten by fishes or snails. Otherwise they will gradually pollute the water.

It's also wise to check the water quality at least weekly, and after 3 -4 weeks or even more when not using starter kits, before putting in any fishes you have to make sure that the parameters measured by the test strip are looking fine.

5) At this point (after waiting at least 3 weeks), you can start putting in the fishes. Fishes must be put in gradually and you must always monitor the water condition. As fishes start to produce ammonia, the bacteria cultures will break it down in NO2 and NO3. If you start to measure the water quality, it should be visible with a slight rise of these parameters. While having non 0 value of these is not necessarily a problem, especially at the beginning, the ideal is a maximum of 5 to 10 ppm. Levels of 20 to 50 ppm are too high and getting dangerous to the fishes. If the levels are quickly rising it means that the filtration/bacteria cultures are not able to break down the harmful waste.

In this case, you can manually try to lower the levels by using some liquid conditioners, like this:

https://www.tetra.net/de-de/produkte/tetra-nitrate...

This must be administered gradually, until the levels are lowering. Also, in this case, it’s okay to continue to add starter liquid to the water as well, as it will raise the bacteria cultures.

Also, once you’ve added the fishes, you must start to make periodical water changes. Some people say 20-30% must be changed at least every 2 weeks, others would say that also lower, 10% might be sufficient.

Regarding water change, pouring in tap water directly into the tank is also a no-go, as it can contain chlorine and other hard-metal particles, which are not safe for water-life. Safe is to let the tap water to rest for at least 24 hrs, and also use some kind of tap water conditioners:

https://www.tetra.net/en-gb/products/tetra-aquasaf...

Again, there are many brands, and any other will do, it’s important only that you keep the recommended dosage.

As the NO2 and NO3 start to lower, it means that the cycling of the aquarium has been completed and you can gradually, I repeat, gradually start to add more fishes.

The tank has limited space, therefore one must make sure not to overload the tank, as it will break the fragile biological balance, so it’s good to have an idea about what fishes you would like to keep, having in mind the size of the tank, and also to make sure that you keep compatible fishes.

Not every fish will like each-other, and also some fishes will grow very large, eventually outgrowing the aquarium. In this case, you must be aware of this and have a backup plan, let’s say a friend with a bigger tank, or a store or Zoo that will gladly accept the “donations”.

There are charts to be found online regarding the compatibility of the fishes (See the attached picture).

Just “Google-ing” freshwater fish compatibility chart will give you plenty of them.

Adding random fishes into the aquarium is not necessarily a good idea. It’s good to know about each species and their needs. For example, some must be kept alone (betta male fish) , some like it shoaling (In biology, any group of fish that stay together for social reasons are shoaling, and if the group is swimming in the same direction in a coordinated manner, they are schooling)

Also there are some species that stay on the bottom of the tank and eat up the excess food and generally clean the bottom of the tank clean. Some prefer to swim in the middle of the tank, while some fishes prefer to stay on the top.

Usually, it’s wise to combine several species that are OK together, but also fill up the tank nicely. It’s not visually nice to have fishes only on the bottom, and to have the rest of it empty.

Also, there are some fishes that are feeding on algae. This is a nice way to keep the algae colony low. Snails are also eating rotten plant leaves or algae, so it’s also OK to keep some of these as well.

Step 8: Aquarium Maintenance

In order to keep the fishes and plants healthy, there are several maintenance tasks that must be fulfilled periodically, otherwise the fragile ecosystem will fall apart and the fishes will start to die. (If you keep plants, they have special needs, nutrients that also must be supplied)

1) The first, and most important thing is to feed the fishes. You can do this manually, twice a day, or by using an automatic feeder. Either way, it’s common mistake to overfeed the fishes, and this will lead to quickly deteriorating water quality. The general rule is, to add as many fish food that can be eaten by the fishes in no more than 2 minutes. You can buy fish food of many types and shapes, but it’s better to combine them: some will fall to the bottom of the tank, some will float on the top of it, and some will gradually fall, that will be eaten by those fishes who are staying in the middle of the tank. Depending on what kind of fishes you keep in the aquarium, the food must be chosen accordingly.

2) Vacuuming the bottom of the tank (also this will do the water change). This must be done by a “special” tool, that looks like this:

https://www.sera.de/en/product/terrarium/sera-gravel-cleaner/

By doing so, you remove part of the dirt that fell to the bottom of the tank, from between the gravel, and also you will remove part of the water that must be filled up again with clear water.

Note: never use tap water, see above the notes regarding how to prepare the water that will be replaced.

3) Periodically cleaning of the filtration system. There are several types of filtration systems. They can be internal ones, that sit underneath the water level, external ones, that are completely out of the tank, and the pump circulates the water out and in the tank, through the filter mediums, or semi-external ones, these usually are located above water level, but below the hood of the tank (typical to compact aquariums). Depending on the filtration medium, this can consist of several sponges (that are doing the mechanical filtration), recipient for the ceramic rings – that are needed for the growth of the bacteria, active carbon filters, etc.

Special note: Never clean the filter very thoroughly. Useful bacteria lives inside the filtration system that must be kept. Always rinse the sponges and the ceramic filters with luke-warm water, but never too warm and never use any chemicals, just clean water.

4) Getting rid of dead fishes: Fishes have, generally, a short life-span. Some can live for more than 5 years, but usually, even if kept in ideal conditions, most of them never live more than 2-3 years. So inevitably, at some point fishes will die. In case this unfortunate event happens, the dead fishes must be removed as soon as possible from the tank. If you leave them there, at some point snails, or other fishes might start to consume them, and they will even start to decompose. This will lead to deterioration of the water quality.

5) Plant “gardening”: Plants, like fishes, will grow and will eventually die. Fishes or snails never eat a healthy plant. If you notice that they are consuming leaves or plants, it means that these are already dead leaves and by eating them they are actually doing a good thing. It’s not wise to leave this task to them, you can remove those also manually from the tank.

Overgrown plants can do much harm than good: If they are too tall, they can take up the light from above and smaller plants underneath won’t get enough light. So, cutting the excess of plants must be done from time-to-time. It must not be thrown out! You can have a friend who will be happy if he gets some plants for free from you.

Step 9: Solution to Common Problems

Despite every precaution being taken, despite every maintenance being done, it could happen that the water quality gets out of balance. Fortunately, there are many brands that produce various liquids that will try to keep or restore the fragile balance in the aquarium’s water.

1) To lower the algae, you can use Algexit or other similar liquids:

https://www.easylife.eu/products/freshwater/algae-...

Note: There will always be algae inside the healthy aquarium. This is not a problem, however if the algae starts to grow excessively, it usually indicates an underlying problem: bad filtration, too much light, etc. Before applying Algexit, the underlying problem must be solved. Also, this shall be used as a last instance, adding snails or algea-eating fishes is always a better solution.

2) To lower the NO2 and NO3 levels, you can use Nitrate Minus:

https://www.google.com/search?client=firefox-b-d&q...

Note: Again, having high levels of NO2 and NO3 (usually above 10ppm) is an indication that the biological filtration is not working well inside the aquarium. The reason for this could be an aquarium that was populated too soon, before the cyclation ended, or can be due to overpopulation. Administering this liquid shall be considered a quick and temporary fix until the underlying problem is fixed.

3) Nutrients for plants: In order to grow nice and healthy plants, sometimes adding additional nutrients is necessary. Easycarbo helps raising the carbon level inside the tanks that do not have additional CO2 system, while Profito is a general nutrient:

https://www.easylife.eu/products/freshwater/plant-...

4) Cleaning the water: Tetra’s Crystalwater does what it claims: removes the brownish color of the water, removes dirt particles and generally restores the water to “crystal clear”. Of course, it’s not perfect like the advertising says, but it can do quite a lot.

https://www.tetra.net/en/produkte/tetra-crystalwat...

5) General water conditioner: It’s good to administer periodically Tetra’s Easybalance. Like its name says, it will keep the water parameters in range. This way, smaller of fewer water changes are necessary and generally the water quality will be better:

https://www.google.com/search?client=firefox-b-d&q...

6) CO2 systems: Carbon and carbon dioxide is a necessary element for plants to grow. This can be found under many forms inside the nature, but in case of a closed system, like the aquarium, the naturally occurring quantity might not be sufficient. In this case, there are systems that gradually add CO2 to the water. These are expensive and usually require more maintenance, so it should be used in case it's really needed. Easycarbo for example, might be a better option.

Manually administering all these liquids and fertilizers can be a time consuming job, but fortunately this can be done automatically as well.

Jebao, a well-known Chinese brand (not so well known here, in Europe) has some 4 channel peristatic pumps than can be programmed wirelessly via an app to do the job on it’s own :

https://www.amazon.com/Jebao-4-Channel-Saltwater-A...

Step 10: Conclusion

Just like with any hobby, keeping an aquarium is not an easy task. In the end, the aquarium tank is a closed ecological system, where balance and harmony should be kept as much as possible. While many people make mistakes at the beginning, wanting to populate the tanks with fishes before it’s ready, once you follow some general rules, fish keeping is not that hard. Fortunately, filtration systems have evolved, water pumps are almost silent, you can find replacement parts in many stores and also water conditioners will help keeping everything under control.

For those who want to keep costs down, budget solutions do exist, maybe some additional manual work is needed. For the lazy ones, or who can afford to spend more on high tech solutions, there are many advanced automatic systems that will offload the maintenance work from your shoulders.

No matter what solution you chose, in the end, all that matters is to keep your fishes happy by providing them a healthy and as-close-to-natural habitat as possible