Male Mollies - Short Lifespan?

[darcy]

Hello,

I have a 20gallon tank I set up last fall (1 bushynose pleco, 6 danio, a pair of mollies). All has been going very well except for the male mollies. My first one died about 4 months ago and now the replacement male seems to be going through the same thing.

He has stopped eating for the most part and sits behind the bubbler most of the time. There isn't any fugus I can see on his body or any outward problems with his swimming or appearance. He looks normal. However, I think he's getting thinner and perhaps a bit less shiny, which could be from not eating.

Is this normal? Do the males just die sooner? He chased her like gangbusters for months, now I wonder if he's just worn himself out.

The female is the same one I've had nearly a year. She's giganto in comparison and seems to be doing great. Has babies every month or so, eats like a pig.

Thank you for any advice,
Darcy

 

[LauraFrog]

Is there any redness, swelling etc around the anus? General loss of condition, refusal to eat and becoming very skinny then dying is quite common with livebearers. The two most common causes are internal parasites and fish TB. Parasites can be treated. The three best medications to use are pyrantel, praziquantel and trichlorforon. Prazi in particular is so cheap that it's worth trying. If this fails, the cause is probably fish TB. This is the nemesis of a lot of fishkeepers, myself included. In the early stages it is undetectable so you can keep on buying carrier fish and not know they're infected. It's also incurable. Fortunately it is not highly contagious. It's spread mainly by the fish eating flesh or droppings of another fish which has it - removing dead fish promptly, keeping the tank clean and making sure the occupants are well fed slows the spread.
There's also a chance that internal bacteria could be the cause, but these infections are usually caused by poor water quality. If that was your problem, your other fish would probably be sick as well. If you want to try it, the remedy for most internal bacteria is tetracycline. I don't recommend bandying it about unless you are fairly certain it might help (or else that the fish will die if it doesn't). I don't personally agree with the indiscriminate use of antibiotics by some people. They are too often treated as prevention, not cure. There are safer ways of preventing illness that don't involve abusing drugs.

 

[OldMan47]

A molly should not be dying in only a few months. When they are in good health they will live for many years. The ones I have right now are about 3 years in my tank and they were almost adult size when I got them. You may want to post your question in the Tropical Fish Emergencies forum where people with knowledge about disease can help you. My own experiences with disease were long ago and at that time I was seldom successful in treating fish. Now I rely mostly on maintaining healthy tanks and avoiding the diseases so I still am not learning about good cures.

 

[darcy]

He was dead when I got up yesterday morning. I tried the Prazi you suggested but didn't work obviously. I think it might've been the fish TB.

It is the strangest thing, no outward signs of anything wrong on his body and all the other fish in the tank are fine. It was the exact same way I lost the previous male about 4 months ago.

Thank you for the suggestions and insight. I haven't decided if I'll get another male.

I know, obviously they shouldn't be dying like this. The female I bought a year ago is going strong! And the two males died of the same mystery problem. Since no one else in the tank has been the least bit ill, I'm thinking it might have been the fish TB LauraFrog posted about.