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I just have a question maybe its stupid but please answer. When they say on a website like a fish needs 100 L Gal i dont know how much in gallon, does it mean if u want to add another u should get a 200 L gal or u can add 2. How can u know how much fish of each type u can add to make ur tank not overstocked.

I'm a bit confused by this question. Are you asking how many gallons is 100 liters? 100 Liters = about 26 Gallons (US)

I think this would be a little easier if you told us the size of the aquarium that you want and what kind of fish. We'll help ya decide what is appropiate for your tank, if that's what you're looking for

-Josh

The question being asked here is this: if a fish is specified as having a minimum aquarium size, do you have to multiply that aquarium size by the number of fishes if you want to keep more than one of that species?

For example, if someone says that 10 gallons is the minimum size for a Neon Tetra, would you need 20 gallons for 2 of them?

The answer to this one of course is somewhat complex. In the case of a Neon Tetra, which is a shoaling fish and needs companions of its own species, the good news is that though a 10 gallon aquarium is specified as a minimum size, you can (with careful management of course) have 6 of them in that 10 gallon. In a 20 gallon, that figure becomes 12, and in the 20 gallon, there would be space for something else as well (e.g., a nice shoal of Corydoras habrosus on the bottom).

With bigger fishes, it's more problematic. Usually because many of the popular large fishes (e.g., Oscars) are strongly territorial. So if someone tells you that you need a 125 gallon aquarium to house an Oscar happily, well you could house two in that 125, but if they're two males, expect them to fight bitterly with each other, probably leading to the death of the weaker fish. A mated pair of Oscars, on the other hand, will live in the same 125 as a single specimen.

Likewise, in the case of Bala Sharks, the baseline setup for those fishes is a 250 gallon. But that is because [1] Bala Sharks grow to 12 inches in length [2] they are shoaling fishes and you should, if possible, keep 6 of them together, and [3] they're very active swimmers. So while 250 gallons is the baseline setup for Bala Sharks, that baseline setup is defined on the basis that the fishes need to be kept in a group, and need a LOT of swimming space because they're fast, active fishes. Something the same size, but much more sedentary in habits, would probably need a correspondingly smaller aquarium.

Aquarium size specifications should be based not only upon the adult size of the fish, but additional needs based upon such details as behavioural requirements. So, big shoaling fishes should have very large aquaria specified as baseline setups BECAUSE they're shoaling fishes and you should be keeping at least 6 of them. That's why Tinfoil Barbs are an impractical species for anyone with less than 150 gallons (and this species should preferably be given more space than that), because the species reaches 14 inches in length and is a shoaling fish. The same aquarium that would be needed to house 6 Tinfoil Barbs would probably house a larger number of much more sedentary fishes of the same size, assuming that those sedentary fishes weren't territorial and eager to fight with each other over territory.

To quote an extreme example, there is in existence a fish called the Helicopter Catfish, rejoicing in the scientific name of Wallago attu. First of all, you would not be able to keep anything else in the same aquarium, because the Helicopter Catfish would probably eat it, so you would be stuck with a one-fish aquarium if you decided to keep that species. Second, the size of aquarium you would need in order to keep this fish would be colossal ... this fish reaches seven feet in length and can tip the scales at 120 lbs in weight, and so you're looking at keeping this behemoth in a swimming pool, not an aquarium! A baseline setup for this fish would be, wait for it, a five thousand gallon tank - that's an aquarium the size of my living room! Furthermore, that gargantuan aquarium would be committed to that one fish, and that one fish alone, until the fish expired.

Now, according to Practical Fishkeeping magazine, that fish weighs as much as seven Jack Russell terrier dogs (eek), or, in fish terms, it's the equivalent of 45,000 Neon Tetras (yes, you read that correctly!). Now, if you built that huge aquarium, could you put 45,000 Neon Tetras in it? Yes you could - and what's more, you'd have space for a lot of other small fishes too! Because those 45,000 Neon Tetras would, paradoxically, produce less biological filter loading than the one Helicopter Catfish. How you would go about feeding a shoal of 45,000 Neon Tetras is a question I'll leave open, but doutbless someone one day might have fun trying!

So, if a minimum aquarium size is quoted for a fish, you need to check a range of facts before applying that knowledge (which of course any reasonable fishkeeper should be doing). Is the fish in question happy to live as a solitary specimen, or will it require companions? Is the fish a shoaling species, a sedentary basking species, or a territorial one? Are there special factors that need to be taken into account? For example, in the case of Melanochromis chipokae Mbuna, you can keep several in the same aquarium, but you'd better make sure there's only one male in there unless you want World War III to break out in your aquarium! Are you planning a species aquarium or are you planning some kind of community? This too impinges upon the final decision. For example, if you decide to keep those Melanochromis chipokae Mbuna, and you want other Mbuna in there as well, you had better make sure that the other Mbuna are hardcore ruffians like the chipokae or the chipokae will probably destroy them!

Oh, and for the record, I advise people NOT to even THINK of trying to keep a Helicopter Catfish. Apart from the fact that the aquarium it needs will cost something like $50,000 to set up, and probably cost $10,000 per year to run, the Helicopter Catfish has a large mouth, and if it feels threatened, it will bite ... that includes taking large chunks out of your forearm if you're not careful! In fact, a large adult is probably capable of amputating human limbs if given the opportunity, and thanks to its large array of backward pointing teeth, even if it doesn't amputate, it will leave behind a very serious wound. Best left in the wild, this one, or left to the staff of a very well equipped public aquarium.


Panda Catfish fan and keeper/breeder since Christmas 2002