I tried several temporary solutions that only lasted until my son could stand a little better or reach a little higher until I finally found one that worked. It can be done for about $10. The first thing you need is a fish tank that your child can't move (mine weighs about 60kg with the water in it). It won't help you to child proof the tank if your child can push it off the table. The other needed equipment is--
- Aluminum wire (or coated wire of any sort)
- Padlocks (small luggage locks-- I got mine at the ¥100 store (The Japanese dollar store))
- A firm plastic tank lid (or any firm plastic that can be used for the lid)
- A power drill
- Wire cutters
The basic idea is to not think about toddler-proofing a fish tank: it’s to think about anyone-proofing it. Toddler-proofing really only works a few months until the child grows a little taller or a little more cunning. If an adult can’t open it, then you know you’ve done a good job.
1. Get a lid
Glass lids will not work because they are to fragile for a toddler. Plastic lids are made for smaller tanks, but they were too small so I laced two together using aluminum wire. If you can’t find an appropriate lid, you can make your own. If the plastic is not strong enough, you can sandwich a few sheets of weaker plastic together to make it stronger.
2. Drill holes
You need to make holes for the aluminum wire. If the rim of your tank is plastic, drill two holes on the lid and two holes on the rim for each padlock. If the top of your tank is metal or there is not enough plastic to drill, you’ll need to glue something to the side of the tank to hold the wire. A loop of something fabric (and flat) would hold better than a piece of metal or plastic in most circumstances. Epoxy or superglue should be able to hold it down. If your filter is on the top of the tank, you can drill holes in the lid of that too to lock it down nicely.
3. Loop the wire
Aluminum wire has sharp ends when you cut it, so make sure to put those on the inside. Twist the wire together a few times to see if it’s strong enough.
4. Lock it
Plastic coated padlocks are better (both aesthetically and hygienically) for houses with small children. Since you’ll have a lot of identical keys and identical locks, I recommend marking both the key and the lock with a permanent marker to tell which is which. If for some reason the other steps won’t work, find someway to padlock your tank. Any other way is just biding time until your child gets a little taller or smarter.
To feed the fish without having to open the lid, cut (or grind) a small divot on the edge of the lid to drop the food into. I don't feed the fish while my son's watching, just in case he gets any bad ideas. Now I just need to keep my son away from hammers and large rocks and the fish are safe!