Male Mollie Looking Bloated

I added 6 male mollies to my 74L tank last week and they all seemed to have settled in well. However, today I’ve noticed that one of them has become a lot fatter and keeps swimming to the top of the tank. Could something be wrong with him or is he overfed? I try to make sure not to give them too much food and the others don’t seem to be as fat. I did a water test as well and it seems to be fine.

The fish in the photos is a female, and she's pregnant.

Can I suggest you take a close look at the other mollies, specifically at the anal fin. That's the one right in front of the tail on the under side. Females, like the fish in the photos, have a fan shaped anal fin. Males have a rod shaped anal fin. If it was the shop worker that selected your fish, they either caught a female by accident or they can't tell the difference so you need to check exactly what gender each of your fish is.

If the other 5 mollies are males, you do have a bit of a problem because these fish, like the other common livebearers, should be kept with at least 2 females for every male. The reason is that male livebearers constantly pester females, and you need more females than males to give each female time off while other females are chased. With 5 males to 1 female, she will be extremely harassed.

Thank you for responding! So I’ve taken a look and it appears that there are 5 females in total and 1 male as only one of the fish has a rod shaped anal fin. Do you think I should get another 1 or 2 males?

bubblexkii said:

Thank you for responding! So I’ve taken a look and it appears that there are 5 females in total and 1 male as only one of the fish has a rod shaped anal fin. Do you think I should get another 1 or 2 males?

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If that's the case then you're going to have aloooot of fry!

don't get more males, just leave it as is.

5 females and 1 male is not a problem. The girls will all get time off and he'll be very happy.

But be prepared for fry. With 5 females, I would just let nature take its course. If you try to save all the fry, there won't be any room left in the tank in a few months

will do, thank you