Sick Livebearers

[Murphus]

Hi guys, I'm new to keeping tropical fish! I have a 35l aquarium that has been set up for about 6 weeks now. I have two swordtails (they were both females but one now appears to have turned male...) and two dalmatian mollies (female). A few days ago I noticed that one of my dalmatian mollies looked a little chubby, and since I've only had them two weeks I presumed that she must have been pregnant (or carrying sperm) when I bought her.

This afternoon I got a little clown pleco, and also some live plants (I'm not sure of the species but they are long grassy reeds, and I'm sure they just called it 'grass' in the shop). After introducing the pleco and the plants everyone seemed happy, but I've come home three hours later to find all of my fish are suddenly very fat! They also seem to be pooing almost constantly. Are they sick? If so, what should I do? I've removed the plants in case they are in some way to blame for the sudden decline in the health of my little fishes, and have done a 30ish% water change.

Thanks in advance! I'm very worried

Also all the water parameters are fine, and I only feed the fish once a day (flakes).

 

[N0body Of The Goat]

What are the exact parameters and how are you testing (liquid test kits or strips)?

How did you cycle the tank/filter?

35l is far from ideal for these livebearers, they can be fiesty like many livebearers (my Ilyodon xantusi give as good as they get with my Lionhead Cichlid youngsters), bullied tankmates will have nowhere to run to in order to escpae attention in a small tank. I personally would only put Swordtails and Mollies in tanks in excess of 3-foot long, not only for bullying, but also because the females especially of both species can easily reach ~12cm.

Personally, I would put ~10ml of the currrent tank water to one side (to test later) and then do a ~95% water change, as I suspect you are effectively "fish-in cycling" with inappropriate fish in a small volume tank, giving an ammonia and/or nitrite spike.

 

[Murphus]

I am using test strips, so perhaps my parameters are inaccurate, but my strips indicate that nitrite and ammonia is 0, and nitrate is about 5. I fish less cycled the tank for 3 weeks before adding any fish, then my swords were added, and 2 weeks later my mollies. Today is two weeks since my mollies were added. I have taken the advice of two pet stores regarding what fish I can have, and neither have suggested that my tank is too small (though I appreciate that staff at the LFS are often far from knowledgable!). Thanks for the advice, I shall do another water change now and hope for the best!

 

[the_lock_man]

When you say "fishless cycled", did you add bottled ammonia to the water during this time, or did you just let the filter run for 3 weeks?

 

[Murphus]

I didn't add ammonia, but I did have mature filter media from a friend with a long established tank.

By way of an update, following the water change, keeping the lights off, and fasting the fish today, all of the fish have now seemingly fully recovered! I've done another 50% water change today just to be sure, but I think what may have happened is that the fish gorged on the live plants while I was out! Does this sound plausible?

Also, I've ordered an API master test kit, so no more inaccurate test strips and undue worry! Thanks for all the help!

 

[the_lock_man]

In that 3 weeks, you haven't "fed" the bacteria in the mature media, so they will have practically all died off. When you get that kit, monitor your ammonia and nitrite levels daily until you are sure that levels won't rise above 0.25ppm before the next water change.

THe livebearers wouldn't eat the plants - I don't know about the plec. Perhaps you're feeding the fish too much - their stomachs are on;y about the size of their eyes, and they have no mechanism to tell them they're full.

 

[Alm0stAwesome]

Maybe they feasted on baby fish?

 

[Murphus]

I'm not sure about the possibility of fry, my white molly (who I originally suspected was pregnant) is still chubby, and I wouldn't have thought she'd be big enough to drop any time too soon - what do you guys think?

This is the mollies when I first added them to my tank.

And this is her today.

Do you think she is pregnant? Or is she perhaps ill? My test kit will come tomorrow so I will be sure of the water parameters then!

I don't think I feed them too much, I just feed them a pinch of flakes once a day (morning). I did, however, put an algae wafer in the tank on Sunday for my plec which was gone when I came home Monday to find them all fat (much too fast for my plec to have done, from what I read), is it possible that they all munched on this, making themselves balloon?