Bully Fish

[Cyber Fish]

I have had aquariums for years but I now have a funny problem. I have an aquarium with many different fish but one in particular (a Gourami) has become a really bully!!! The fish in this tank range from Gouramis, plecostimus, neon, dianos, and tetras. Now, this tank has been up and running for about 1 year now with the same fishes (no new ones). But in the past week on so on of the Gouramis named "Peetie" has been bullying all the other fish and now they cower in the corner of the tank leaving the rest of the tank open for Peetie. Now I know that Gouramis are territorial and all but they have all been living together for a year now with no problems. Why does this start now? And what can I do to stop it ,aside from giving him a view of our sewer system?

Thanks in advance :D

[Eric]

More than likely your gourami has recently matured, it's not uncommon more mature gouramis to become aggressive. Really as I can see the only thing to do is setup another tank for gouramis or give the bully to a friend, etc.

[Alf]

I have to agree with Eric. He has now matured or has become stressed in some way. try a little stress coat. if that does not work than maturity is probably the problem and there is not much you can do for that. HTh

[AquariumPro]

As any fish becomes sexually mature, they will begin to exhibit their natural breeding instincts, which include establishing a territory. If the Gourami has a dorsal fin which comes to a point at the end, it is a male. Females have a dorsal fin that is round at the end.

Like their cousins, the Betta, some male Gouramis can get quite nasty, particularly the Kissing Gouramis, three-spot Gouramis (The Blue, Opaline, Gold, and Platinum - all the same species), the True Gouramis, and the Thick-lipped Gouramis.

You might also try increasing the amount of cover in the tank by adding a lot more rockwork and plants (plastic or real). If there is a lot of open space in the tank, the Gourami will try to claim all of it. If the space is broken up into smaller territories, his instinct will lead him to claim a smaller portion of the tank, usually in a back corner of the tank that is darker and quiet.

Most Gouramis build bubble nests when they mature, and they can't do that if there's good circulation in the main area of the tank. You can effectively change the territory he's claiming by simply directing the flow of a powerhead into the main area of the tank. Doing this, combined with adding more cover, may take care of the problem.

No guarantees that these techniques may work, but these are the things I would try. :D