Cichlids eating another cichlid?

There are a few factors you need to consider when dealing with cichilds. Like you said, you can group certain fish togeather early, but many times as I'll tell others on here, like a Green Terror or Jack Dempsey, fish like this are fish that are a "rule the tank" fish. They do not play well with others. At some point or another, the aggression will begin.

Another common factor contributing to this is tank size too small. Keep in mind, cichlids in general doesn't tell us much. It's always best if you know what species you have. There are different characteristics for example, between South Americans and Africans, especially in terms of water needs. Spacing needs should be addressed as well. So one first thing to solve this, is what size tank do you have?

Second issues is sexing. Males always, or rather, almost always are the more aggressive of the two, for most species. There are some cases where females are more aggressive, but as a general rule, it's the males you need to keep an eye one. You put two say male Red Zebra's in a 20 or 30 gallon tank, and it's a ticking clock until a showdown starts. They may start out less the one inch, but as you plan your stocking ability, you never base that on what you see now, but rather what size will they end up to be. A space like that is too small to allow for enough "territory" for 2 males to safely inhabit. So another possibility is that you have too many males in too small of a space. So species and if you know the sexes of them is the second clue that would be needed to assess this for you.

Mating also comes into play. By far, many Cichlids, African or South American are mouthbrooders. During this time, the female, USUALLY is the one that carries the eggs for three weeks in the mouth. Convicts by far are one species I can say that when mating comes around, they become extremely aggressive towards any other fish that might come in their area. Or if a male is trying to entice a female to an area to spawn, it may well be a matter of him chasing off other fish to prepare for spawning too, so again, it's really necessary to know what fish you have. If you do not know what fish you bought, pictures or video's will really help.

I take it you are talking about malawi's? This happens from time, ive come across this, its to do with maturity and wanting to breed etc.

Yes, if left in the tank he will die, similarly if he is removed into a quarantine tank, when reintroduced he will be bullied again for being a newcomer and stumbling on other territories.

You either need to remove the dominant male or the one being bullied. If you decide to seperate the bullied fish, are you able to reintroduce him with some new fish to spread the aggression?

Cichlids are territorial. If they were young when you got them, they're now at an age where they're thinking of forming territories. The bullied one has missed out.

I don't think I'd risk putting him back into the community. Get him another tank and keep him seperate. His wounds will heal, but my guess is, he'll always be an outsider.

Well, fish's minds can still grow mature. They can still be 'agressive' until they grow up. Is the one cichlid bullying older than the one being bullied?

CC

is the cichlid that is getting bullied younger than the rest?

What Cichlids have you got?

re establishing order in the tank aka hierarchy