my fish are fighting :(

Question
Hello again. I think i have sorted out the problem with the water quality now and i'm feeding the fish the correct amount of flakes. One of my fish has white spot so i am treating it and it seems to be recovering now.

A few days ago the healthy fish started "nibbling" on the sick fish's fins and chasing it round the tank,it started looking distressed and its condition deteriorated. I don't have another tank so i seperated the tank in half using a bit of perspex and the sick fish has vastly improved and is looking healthier by the hour.

I though that it could just be the healthy fish picking on it because it was weak but i was wondering whether they will stop fighting when the other fish is healthy again or should i seperate them into different tanks/ get a bigger tank.

I can't really keep the perspex in the tank because the sections are too small to permenantly keep a fish in.

thanks again,
Erica

Answer
Hi Erica,
Thanks for the follow up question. You did exactly the right thing to partition the tank. This is just temporary. When everyone's feeling better, you can take the partition out and things should be fine.
You might also give the aggressive fish a little bit more food. However, fish will attack a weaker fish and try to kill it. It is their instinct to put a sick member of the school out of its misery. In nature, a school has to move on and they know a weaker fish will hold them back. Birds are the same way.
Some people settle into just having one fish. Don't worry, they don't get "lonely" as long as there are humans around. Some fish are territorial. They think they own the whole tank and will attack whatever you try to introduce.
Just make sure that both fish are fully healthy before you remove the partition. Keep up the healthy diet and both of them should recover fine. They can grow their fins back.
Nori