Firemouths are great fish. They sometimes get aggressive, but not a lot as long as you keep them with other cichlids, but you can keep them with semi-aggressive type fish. Good fish and will eat most things you feed them. My 2 are about 10 cm and are beautiful. I like this fish and if you get them you should too.
I've had a firemouth before and he was the king of a 110 L tank. He was housed with a smaller jack dempsey and two small convicts. He would flare out his gills to challenge the dempseys. I got another firemouth a month after getting the first, which was a mistake. When I set the second firemouth in, they fought nonstop. I guess it was because a 110 L is too small to house two firemouths, and they were both males. Since firemouths are from Central America, they need semi-hard water. They are hardy fish that can take colder water, but it's best to give them tropical heated water like all the others.
Just to say that the Firemouth is a great fish. Of the cichlids I have, he has to be my favorite. However, he freaked out the angels and the keyholes when he first came, so much that something had to give and I knew he had to go. So I bought him a 60 cm tank and put him in there with a dwarf Gourami, who was a bit of a bully in his community tank, and they both live there happily. The firemouth are great fish, I highly recommend them. They would probably be great in a community tank, but I hate the sight of bickering :o(
I have 6 firemouths (3 males and 3 females) in a 120 cm, heavily planted community tank with mainly swordtails to supply live food. The male firemouths are 10 cm long and so far have not formed pairs with 7 cm females. I have found them to be excellent community fish, that tend to leave the other fish alone. They save most of their activity for their brilliant flaring displays to each other over territory, that I never seem to tire from watching. I'm looking forward to seeing if I can keep two pairs in the tank and I have another 90 cm tank on standby if I can't. I cannot recommend these beautiful cichlids enough to the beginning aquarium enthusiast.
A very fun and attractive fish. Although they are smaller than many of their counterparts from South and Central America, they are completely able to protect themselves against bigger species. I had 4 of these guys in a tank vith 2 blue acara´s, 4 convicts and 2 large severums. The firemouths didn´t hesitate to attack the acara (who was 3 times bigger) and protect his territory, they got some battlescars, but they healed quickly. Overall a beautiful and fun fish to watch.
I've had firemouths on and off for years now. I have one firemouth that is very aggressive, and I've had some that went in my community tanks with angelfishes and tetras. Their breeding habits are the same cichlid fashion. They make great parents, and are very protective. Their breeding colors are the most beautiful of any cichlid I've had the pleasure to breed. The males have the most fire red color (hence the name), and the females are not exactly drab during this period either. They require at least an 80 L tank, nothing less. They normally mix well with other cichlids, and make a great addition to a cichlid tank.