Dalmation Molly Swimming Sideways and Upside Down?

[BlackMollyJenny]

I got my Dalmation Molly a week ago and the pet store worker there said that he was doing well and was ready for a new home and he has been acting really odd. He is swimming upside down and sideways and sometimes rests on the ground in these positions. He is still alive but I am really afraid he's going to die tonight, any ideas of what this is or and/or how I can treat it are welcome.

He's in there with
5 guppies
7 guppie babies (which will probably die off soon)
1 other Dalmatian Molly
2 sucker catfish
1 loach

My tank has been set up for about three mouths and was bought all brand new, it's a 20 gallon tank, all glass

A nother random thing he's doing is 'shivering', i don't know what this is eather so... Any way please help!!!

 

[Coursair]

Do a large PWC. Test your water. Your tank is still very new.

 

[BlackMollyJenny]

Thanks, but what does PWC mean?

Just noting, when I got up and turned on the light he had been laying sideways, he's still alive still but he had a lot of trouble swimming normally. I tapped on the glass and he swam up, most of it was floating, straight to the surface. Could it be a swim bladder issue?

 

[BlackMollyJenny]

I'm sorry to keep updating you on this bit I care for this fish

I've done a bit of reading and think it might be swim bladder disease or wopsy (I don't know if I spelled that right) how can I tell this apart and/or treat it? I don't want him to die. One of my other fish is really concerned about him and is "kissing" his tail and body.

He has trouble staying near the bottom on the tank and the other fish (except for the other fish who is concerned) stay away. He has also been "shivering" in the past but doesn't do it anymore. He'll float down into the gravel head first, and sometimes fall sideways. Then he'll float back up to the surface and attempt to swim around a little more and float back down. Should I separate him from the other fish somehow? How can I help him?

 

[hackerbee]

PWC is a partial water change. Change 25 to 50% and see if that helps. You should also test for ammonia, nitrites and nitrates to look for reasons the new fish might be stressed.

 

[BlackMollyJenny]

Thank you but unfortunatly he died a few hours ago but I am still afraid that other fish might start to do the same thing

 

[hackerbee]

Sorry about that!

Do test your water as it is very possible that nitrates are building up to unhealthier levels. Fish can slowly acclimate to higher levels of nitrates that new fish can't tolerate.