A youtube video showing the filter in use in a turtle tank with the spray bar hooked up, would work fine in the small aquarium as well.
Because these filters are placed and work inside the aquariums, they are limited in the size as well as the filter capacity. Therefore, internal filters can only fit for small to medium tank sizes. These filters are popular for low water habitats like turtle tanks. They are also sometimes used to supplement canister filters or external power filters in larger tanks, but their visibility within the tank often makes them less than ideal.
I recommend these internal filters because its capacity is large enough to accommodate some biological filter media that other internal filters can’t do. The flow rate and direction of the water output can be adjustable that makes this internal filter ideal for smaller tanks with small fish. If you love to use a traditional internal filter, are the best and cheapest ones to buy. They come in various sizes for aquariums up to 40 gallons.
Tetra® Whisper Bio Bag Cartridges
Fluval® External 206 Canister Filters
Remember that even if you take these precautions, and make aneffort to make the small aquarium or fish bowl a better place for yourfish, you still have not overcome that small water volume issue, whichis the primary problem with these fish tanks. Adding a filter oragitating the water will not significantly reduce the maintenancethese small aquariums require.Everything I've read about keeping aquariums always ALWAYS says that a small tank is a bad idea for a beginner (the reason for this is the fact that even a small amount of fish waste can drastically change the water quality when it's dissolved in just a little water, so you need to keep a careful eye on water quality, and understand the factors that affect it). But what if you just want a little fishbowl on your desk (or wherever), and don't feel like sinking over hundred dollars into setting up a respectable size tank (i.e. 10 gallons or more, and believe me, it will add up to that much or more, with tank, stand, hood, filter, air pump, gravel, decor, chemicals, etc). On the other hand, you don't want to just have a betta death-trap, where you change the water from time to time and hope your fish doesn't die. You can always shell out $30 - $80 on something like the Eclipse Explorer (prettier kinds are on the higher end of that range), and have a relatively complicated setup to clean and maintain to boot. Or you can set up a very simple and very effective filtration system in your existing tank for about $12. However, I must point out that a filter doesn't replace the need for frequent partial water changes.Introducing a cheap (around $4) small tank filter called "Discard-A-Filter" (I'd say one of these is good for an aquarium of up to 2 gallons. Use two and you could probably go up to 5 gallons. Note that you need an air pump to operate it, but these can also be quite cheap and you only need one, even to run two of these filters.) The filter is so cheap because the manufacturer expects you to just toss it in the trash every month and buy a new one (which would actually end up costing you quite a bit over the life of your fish). However, and this is not because I'm so eco-conscious (I'm reasonable: I don't go overboard, but do try to limit unneccessary waste when I can), the idea of just chucking a relatively large, sturdily manufactured object just rubs me the wrong way. It doesn't help that I happen to know that the only thing about the filter that stops working is the activated charcoal (and a smaller quantity of zeolite, which you can also, optionally, add), which absorbs harmful chemicals from the water -- it's absorbed everything it could, and has to be replaced with a fresh batch, there's no getting around this one. So, in this instructable I'll show you what you need to do to keep happily and cheaply reusing this filter, as well as improving its function.Meet Sparky, a micro filter for fish tanks that only costs $3. It is so simple to make and it is the perfect size for a betta tank or another small aquarium. If you want to use it with a larger tank, you can just double up!