How much space do cichlids need? The answer to that question boils down to two factors – the size of the cichlid(s) you want to keep and how many you want sharing the same tank.
But before answering the question above, I would start with asking yourself the following:
- What is your intent with the tank the fish will be in? In other words, are you wanting to breed or do you just want to show them?
- Do you want multiple cichlid species together in the same tank (community tank) or do you prefer species only?
- Are the cichlids you want to keep dwarves (< 5 inches in TL)?
- Are the cichlids medium sized (between 5-10 inches)?
- Are the cichlids large species (> 10 inches)?
Cichlids, as a rule, are aggressive fish, especially with respect to territory establishment and breeding behavior. Many of them are also predators (i.e., they’ll eat other fish, including their own).
Many cichlid species aren’t hard to breed but when they do so, other tank occupants are often considered threats and are dealt with accordingly. Multiple cichlids in a single tank, conspecifics or otherwise, might all get along great. That is until a m/f pair of the same species decide to breed. At that point, they may no longer tolerate anyone else in the tank. Even a tank full of a single fish of multiple species can result in hybridization. The same dangers apply in that situation.
Because almost all cichlid species are also territorial, keeping multiple specimens together (conspecific or otherwise), can also be problematic. This issue is often mitigated by keeping so many fish together so that no one can establish a territory. This is called controlled overcrowding. The danger here is that sometimes cichlid keepers house too many fish together in too small of a tank.
As indicated by the questions above, the size of the fish also matters. Please disregard the ever-popular myth of one inch per gallon rule – meaning the minimum size tank by volume is dependent upon the length of the fish it houses. Instead, I like to use the rule of 10 inches of tank length for every inch of fish – meaning the length of the tank should be 10x longer than the largest fish. For example, in my personal opinion, a 10-inch fish shouldn’t be kept in a tank less than 100 inches in length nor should a 3-inch fish be housed in a tank shorter than 30 inches, etc. I believe this is a more logical and ethical formula.
Keeping multiple fish in the same tank requires some consideration also. Would I keep 20 fish of 10-inch length each in a 100-inch tank? Yes, if the tank was also decently wide and deep. I wouldn’t if the tank width was only 12 inches, and it was only 12 inches deep.
If I am breeding a pair of 10-inch fish, I won’t be keeping 18 other fish of the same size in there. By the same token, I might not keep more than a breeding pair of 3-inch fish in a 30-inch tank. For the latter, I probably wouldn’t keep the small pair in anything less than a 48-inch tank. Of course, a lot of the tank mate decisions for tanks housing breeding pairs depends on the species of the pair. Not all cichlids are equal in tenacity when breeding.
Though the above suggestions and recommendations apply to nearly every situation, experienced cichlid keepers/breeders can (and do) very successfully NOT follow these.
Anyway, I think these are some very reasonable and responsible considerations when deciding how large a tank to buy for your cichlids.