Rainbow Shark being a complete bully

[Maddie]

I have a rainbow shark in with 4 severum 6 angelfish and 6 electric blue acara. The flippin shark is a nightmare. He chases the electric blue acaras constantly. They are all just babies (although growing fast).
Do you think this shark will settle down or do I need to remove from the tank. Honestly the acaras are fast but just as well they are like little super balls bouncing around the tank. I cannot be good.

[Andys temperate tank]

I may be wrong but rainbow sharks need massive tanks and to be kept as a group.

I'm not sure it will settle down. How big is it?

[black ghost]

Rainbow Sharks are solitary territorial fish, that are aggressive towards their own species, and often also towards other fish. You’ll need to remove it.

[Maddie]

Aggresive !!! Of all the fish in the tank this is the only one I didn't look up before I bought. It looked so cute and I asked the man in the shop and he said it would be fine so I trusted him. Should've done my research. Is there a chance this little bugger will settle down when the Electric Blue Acaras get bigger ? The Severum and Angels he sort of leaves alone at the moment.

[black ghost]

Aggresive !!! Of all the fish in the tank this is the only one I didn't look up before I bought. It looked so cute and I asked the man in the shop and he said it would be fine so I trusted him. Should've done my research. Is there a chance this little bugger will settle down when the Electric Blue Acaras get bigger ? The Severum and Angels he sort of leaves alone at the moment.

Size is presumably a factor, but the ‘shark’ will grow bigger than the Acaras. So I don’t think the aggression will stop. It just wants it’s territory, which is about a square meter, with no one else in it.

[black ghost]

Rule no 1 in Fishkeeping. Don’t listen to shops.

(Some are good but most aren’t. Always check what they’ve told you).

[Maddie]

SO ... what to do with the beast ? I feel so guilty. I have a 5ft tank but clearly that is not enough. When I get more stuff in the tank might it settle if it has it's own 'space'. The tank is pretty bare at the moment. Willt he acaras be stressed by this or is it part of life for them anyway ?

[black ghost]

The only way it will stop is if fish aren’t constantly coming too close. Which isn’t gonna happen, and all the cichlids are slightly stressed just by its presence. The Acaras are extremely stressed and heading for disease. You must remove the shark...

It’s not normal for any fish to be bullied, ever. If they’re chased off they’ll go, and they won’t come back. They can’t do that in a tank.

Stress causes disease.

[Martinspuddle]

Rainbow shark (Epalzeorhynchos frenatum) are not a very good choice with Cichlids.

In the late 1980's I kept one successfully was in a 5 x 2 x 2" aquarium with Clown Loaches, Giant Danios, Kissing Gouramis, Synodontis nigrita, Rosy, Tiger Barbs, Buenos Aires Tetra plus a couple of medium sized Hypostomus plecostomus. In hindsight the aquarium still wasn't big enough for all of them.

Believe @Staffylover had a large one in her large community at one time.

[black ghost]

They’re guarding their feeding territory. They’re grazers on aufwuchs by nature. All they need is for no one to get too close to their patch. Trouble is half the fish we keep have no concept of territories or even ‘personal space’ and will never work out where they’re not allowed to go.
Most cichlids are also territorial (all of them when breeding) so there’s not much chance of a cichlid/this-type-of-shark mix working.
Bottom line is they’re not a great community fish. It can work in a big tank but it more often doesn’t.