Originally Posted by dancexonxwater
I used to have three black mollies in my 10 gallon tank. However, one recently died. I have noticed over the past week that the two remaining mollies (one adult male, one 7 month old female) have really just been constantly nipping at each other. The male now has some sign of fin rot. So I'm treating the tank with Maracyn TC, but I'm wondering if this is due to my fry? Or the stress of losing his fish partner? I've been wanting to get new fish, but not if this one is sick
I bought a cory cat last week, but he died in the matter of two days! It was so sad.. My water quality seems to be fine. But my main concern is that perhaps they are lonely with just the two of them? Is this maybe th reason for the stress? Would stress cause them to become aggressive?
Mollies can be aggressive and usually are recommended for tanks of at least 20 gal with 30 being better yet. There simply isn't room in a ten gal for them to avoid each other or escape to a safe area. The mollies will do well in freshwater ,but seem to do better in slightly brackish water and many add approx one tablespoon of aquarium salt per five gal of water for molly only tanks. Salt should not be added directly to the aquarium but should be dissolved first in new water that you add to the aquarium during weekly 20 to 30 percent water changes.
Not many other freshwater fish will appreciate the salt even at this relatively low level. Catfish and loaches seem to not like salt at all.
Mollies are herbivores in large part ,and need algae based flake foods or spirulina based foods as staple portion of their diet.
One male and one female molly will result in the constant nipping you are seeing by either the male who is interested in breeding,or sometimes by a female who for reasons known only to her ,finds the male unacceptable.You need to have a ratio of one male to four females and this will require a larger tank as mollies can get to three or four inches and as mentioned,,need room to flee from the advances of males and or females who can get aggressive especially during breeding times.
Water in the aquarium for mollies should have pH of 7.5 to 8.0 and gh of 12 to 15 in my opinion . Must also read zero for ammonia and nitrites,and nitrates should be near 10 ppm for mollies who seem to do poorly with elevated nitrAtes that also work to lower the ph over time and thus produce softer water that they don't do well in . Mollies also prefer warmer water with temps of 80 to 84 degrees F in my expierience.
I would perform 2 to 3 gal water changes each week in a ten gal tank and I would purchase my own test kit that uses drops of liquid rather than the paper strips which by most accounts,, aren't all that accurate. The API Freshwater master kit is used by many. Hope some of this helps.