New Mollies Swimming Vertically

[jnms]

I purchased a batch of mollies today - 19 in all to go into a 200litre tank (that is fully cycled). At the moment they are in a 100litre temporary quaranteen tank.

Water perameters are:
Ammonia: 0.0
Nitrite: 0.0
Nitrate: 20
Ph: 8.0

Problem is the mollies keep swimming vertically. They do this for a short while and then start swimming normally again. Any ideas what this could be?

 

[SchottayB]

Not sure what the problem is. Hope someone says as one of my Tetra started doing this but the other way round, tail up head down

 

[alysonpeaches]

The ones that are swimming vertically aree clamping their fins to their sides. This is a sign they arent altogether happy. It might be because of the move and change in water conditions, it might be a sign they are coming down with an illness, or it could even be that they are feeling bullied or threatened by another fish or feeling overcrowded.

When I last saw one of my mollies swimming like that it was the male who is somewhat smaller than the female. He had been chasing her to mate, she got fed up with it and turned on him and gave him a bit of a nip. Then he started to swim like that.

You will just need to keep observing the ones that do it and try and eliminate any possible stressors. It might be that they are feeling a bit crowded in their new surroundings and have no where to hide, it might be that one particular fish fancies himself as the boss and is establishing a sort of pecking order.

Have you got any plants for them to hide amongst and to break up the line of sight, as this often solves bullying problems. Otherwise, keep checking the water to make sure conditions arent deteriorating, as this could be another reason for clamping fins.