Originally Posted by jenevey
We have a freshwater tank (26 gallon) with 2 yellow tale male guppies, 3 zebra danios, 2 cories, and 8 mollies of different types 5 female, 3 male. Just today I noticed one of the male mollies hanging out at the bottom of the tank and swimming a little awkwardly. As I observed him throughout the day I notice he's hiding out in the corner of the tank low to the rocks and still swimming pretty hard. I checked the water levels and ammonia, nitrite and nitrate are all at zero. (I used the API drop kit to test.) We are using aquarium salt as prescribed by the LFS at the levels safe for freshwater fish (and have been for 2 months). I did a 6 gallon water change today and vacuumed the rocks as it was the scheduled time to do so. He's not eating much. None of of the other fish seem to be in any distress. I can't figure out what's wrong with him. I looked him over for ich and velvet and don't see signs of it. We are pretty new to raising/keeping freshwater fish therefore I'm new to troubleshooting fish illnesses. This tank has been up and running for about 4 months now. Any ideas?
Here's a link so you can see what he's doing (please ignore the sounds of Dora in the background.) http://www.youtube.com/watch?v=YYpmDUESlZQ
Any help or ideas on what might be wrong are greatly appreciated.
I might check the pH of the tank. Mollies and guppies prefer hard alkaline water with ph between 7.5 and 8.0 and tend to fair poorly in the long run when kept in soft acidic water.
If biological filter is working I would expect to see some level of nitrAtes unless the tank is heavily planted with live plants.Mollies and guppies also prefer warmer water than the danios and cory's appreciate with 78 to 82 degrees being about right for guppies ,while mollies are quite comfortable up to 84 degrees F.
Livebearer's appreciate considerable vegetable matter in their diet and I might consider Spirulina flake or foods containing same along with occasional brine shrimp and bloodworms.Have had good success with Spirulina based Brine shrimp by Hikari and Omega one veggie flakes with livebearer's I've kept.
Weekly water changes of 30 to 50 percent taking care to clean filter material in dechlorinated water or old water you take out during water change is good practice.
mollies in particular seem to do poorly in cool water or water that as mentioned, is soft. some will live for a few months,others will not last but a few weeks.
You make no mention of babies which I would expect to be mumerous in 4 month old tank with both male and female mollies but perhaps water is not to their liking, have seen this happen and fry are usually deformed and or die within a few days,weeks.
Mollies in particular just don't seem to do well with pH levels much below 7.5 in the long run or in cooler water in my expieriences with them and I might review water parameters.
Might also make sure the fish is male, have seen females exhibit the behaivor on video when about to give birth. would make sure there is plenty of floating cover as opposed to caves or rocks for fish to hide or rest in to avoid aggression or attention unwanted. hope some of this helps.