I picked up some small red shrimp for my community aquarium a few months ago. They were fun to watch, but gradually got eaten or sucked into the filter. So I decided to set up a home for the survivors. I also used the aquarium to let a platy fry mature until he was big enough to fend for himself in the community tank.
The aquarium is 8" x 5" x 4". It's one of those pet carriers they sell in the mall with hermit crabs (much too small as a permanent home for any hermit crab.) I added a sponge filter from this instructable: https://www.instructables.com/id/Easy-Aquarium-Sponge-Pump/ , a lighted hood, live plants, a couple of small snails and 4 red shrimp. The aquarium is thriving. It's so fun to have it here on my desk.
Please keep in mind: This tank should not be used for any fish larger than a 1/2" fry. Regular water changes are required to keep your little friends healthy. I usually replace half the water with filtered water every 3 or 4 days.
Step 1: Parts and Tools List
You will need:
- a small pet carrier with a snap-on lid
- a few red cherry shrimp
- a couple of baby aquatic snails
- live plants and moss
- small decorations, I used a glass paperweight
- filtered water and water conditioner
For light and heat:
- a small food container
- a nightlight fixture with cord
- a small bulb, I used a 15 watt picture light bulb. The bulb should fit inside the container with at least a half inch all around. You don't want the bulb to touch the sides of the container once it's turned on.
- painters blue tape
For the filter (thanks laurie0ginale):
- a kitchen sponge, about 1" thick
- a small shampoo bottle from a hotel, washed, chopped, drilled. The neck of the bottle should be large enough to allow your air stone to pass through.
- a small air stone
- 1/4" aquarium tubing, about 2 feet
- a small air pump
- a flow control valve that fits your tubing
- hobby knife
Step 2: Making the Lighted Hood
I had a small food container in the back of my cabinet that was the perfect size. It fits over the trap door in the lid of the pet keeper. I also scrounged a light fixture from my Christmas decorations. Your hood will be unique, based upon whatever you keep in your cabinets and holiday decorations.
Cut a hole in the side of the container to accommodate the light fixture.
Use a hobby knife to drill small holes in the bottom (soon to be top) of the container. To do this, just push the tip of the blade into the plastic, then rotate the knife several times. The more you rotate, the bigger the hole. You will need several holes to keep the light bulb from over-heating. At least 6, 3/16" holes should be sufficient.
Insert the light fixture. My fixture has a metal spring to hold it in place. You may need to attach your light fixture with tape or hot glue.
Screw in the light bulb. (How many DIYers did it take? Just 1, if you really did it yourself.) Make sure the bulb does not touch the sides of the container. A 15 watt picture bulb emits enough light to keep the plants happy and enough heat to keep the shrimp and snails cozy.
If necessary, cover the outside of the container with blue painter's tape. That bulb was just too darn bright to look at through the clear plastic container. If you cover the vent holes in the top, open them up again with your hobby knife.
Step 3: Sponge Filter, Thanks Again Laurie0ginale
Here's a great instructable with diagrams and everything: https://www.instructables.com/id/Easy-Aquarium-Sponge-Pump/
I modified the design a little so the filter would fit in a much smaller aquarium.
Thoroughly wash the shampoo bottle. You don't want anything to contaminate your tank.
Use the hobby knife to cut off the bottom of the bottle. Drill several holes in the bottom 1/2" of the bottle. See step 2 for drilling instructions.
Cut the sponge into a 2"x2" square. Use the hobby knife to cut a circle through the center of the sponge. The circular hole should be big enough to hold the shampoo bottle. Save the piece of sponge that you removed from the center.
Push the bottom of the bottle through the hole in the sponge. The sponge should cover all the holes in the bottom of the bottle.
Use the saved "donut hole" for a plug. Push the sponge plug into the bottom of the bottle.
Put the air stone on the end of your tubing. Cut the tubing about 2" from the end that will attach to the pump and add the flow regulator. Then attach the pump. Drop the air stone into the top of the bottle.
Test the filter in the aquarium. Then rinse the sponge and bottle in filtered water to remove any contaminants.
Step 4: Assembling Your Aquarium
Put the sponge, with the bottle attached in the bottom of the tank. Wash your gravel, then pour it into the aquarium. An inch or so is plenty. Don't cover the sponge completely, but you will need to have some gravel to weigh the sponge down.
Add your decorations and plants. Add filtered water. If you have an established aquarium in the house, add a little water from it to help start the biofilter process. If not, add a drop or 2 of water conditioner from the pet store. Look for something with live bacteria.
The lid that came with my pet keeper had a small hole, just large enough for the air tube. Push the tube through the hole, then add the air stone to the end. Snap the lid in place, making sure the air stone ends up in the shampoo bottle. Connect the air tube to the flow regulator, then to the pump.
Set the lighted hood in place. Power up the pump and light. Make sure everything works. Adjust the air flow. This is a very small tank, you don't need much air coming in.
Add your shrimp, snails, fry. Enjoy!