What is wrong with my mollies??

[ReefManik]

Ok a couple of weeks back (about 6) I noticed that all my mollies in my main 60g had some sort of swim bladder infection (i think) as all of my black and silver mollies would start swimming verticle and doing little shudders randomly, I treated the whole tank as some of the other fish like a guppy a phantom tetra and 2 red honeys all were wiped out by the swim bladder.
I treated my tank with interpet No. 13 swimbladder treatment for 2 weeks. This seemed to sort things out but to be double sure i took out the 8 mollies and put them in my 15g to moniter them closer. After 3-4 days and a couple of deaths the rest seemed absolutly fine, swimming about, attempting to breed and a black and silver even giving birth.

I assumed all was ok so i transferred my 3 blacks back to the main tank. 3 Days later however the black mollies have been showing the same symptoms, swimming vertically again and shuddering occasionally. Earlier today i noticed the black male was floating around the tank, practically dead, he was being nipped at by the other fish and just floating around the tank like a dead fish, his gills however were still moving showing life so i immediatly netted him out and put him back in the 15g with the silver mollies. Now 2 hours later hes right as rain again swimming around chasing females and eating fine.
Im wondering what id wrong because they are fine in the 15g but as soon as their in the main tank they start getting ill again.
Im having trouble with non of my other fish, gouramis, betta, loaches, plecos, tetras, corys, danios and a ruby shark are all fine and healthy.
Anybody got any ideas?

 

[Vircomore]

This sounds like a compatibility issue. You have some pretty aggressive fish in that tank, and Bettas are known to be especially aggressive towards Mollies because Mollies have a similar body shape to Female Bettas.

I experienced a similar issue when I added Danios to my Molly tank. The Danios are so fast and busy that they confuse and scare the mollies, and a scared molly will often do the "point straight up" maneuver.

You could try adding a small amount of Aquarium Salt to see if that would improve anything - but I think it's a matter of the Mollies not liking a tank that busy.

 

[ReefManik]

I think it may be the danios because now i think about it they started acting like this a week or so after i bought them. Cant be the betta because i got him 3 days ago and hes a shy little bugger hiding in the plants alot staying out of the way of most fish.
Thanks for that vic very helpful i now know its the danios.
Cheers

 

[Vircomore]

If you want to test my advice, before returning the danios - just take them out and put THEM in the small tank where the mollies were.

If the mollies continue to tip, then it might not be the danios.

 

[joeynuna]

There's lots of opinions out there but I truly believe Mollies should be kept in brackish conditions.

What are you feeding the Mollies? I keep Mollies and found when fed only flake food, problems arise. Once a week I feed them peeled peas (crushed so they can pick at the pea) and this seems to help with swim-bladder issues.

 

[mandy2936]

I agree with Joeynuna and Vircomore. First try removing the Danios and wait to see if the Mollies' condition improves.
If not, I would try feeding shelled/crushed peas.

Let us know how it goes!