Trouble with black mollies after water change?

Question

I have a 55-gallon long aquarium, just finished cycling it. The temp is just below 82 F, pH about 7.5. It is filtered by a Penguin 350 and an Aqua-Clear 70, plus a bubble wand.

I have 4 dalmation mollies, 4 sunburst platies, 2 red wagtail platies, and 4 black mollies.

A couple of days ago, I did a 1/3 change with 2 tbsp salt per five gallons new water and AmQuel plus. I fasted them on the same day. Three days previously, I added the dalmation mollies.

I can't figure out why the black mollies got so distressed. They mostly rest on the gravel, and are about 5 days away from giving birth. There is no ammo or nitrite from the tests.

I want to know if I have put them through too much stress, and what I should do or not do at this point.

Answer 1

At this point I would do nothing at all. All of your water conditions sound good for mollies. They should be right at home with that pH, temperature and salinity. Assuming they are all females, they may be trying to hide from the new mollies in the tank. If not, then it could have been from a significant change in the water conditions that has caused the reaction and it will simply take them a few more days to settle down. They could also be closer than you think to giving birth. If you have been counting days to day 28, then you would be about day 23 and that is well within the normal range for them to give birth. This could also be the reason for them staying on or near the bottom of the tank.

MM

Answer 2

He is distressed not only because of the temperatures but also because of the salt. Goldfish should not have salt added to their tanks, also temps even though mollies are better in higher temps 82 is not one of them. It needs to be lower for him. He is a basic cold water fish not a tropical.

Although he can handle warmer water 82 is too high. Your mollies, also should have cooler temps. You are mixing colder water species with warmer water tropicals.

Although mollies are typically brackish to full salt fish, gold fish are not. this tends to bloat them and tends to make them retain water. Remove your mollies, and I hate to say it even if it is to a bowl. They will be better off. Cold dechlor water, no salt no stress coat. Change 1/2 of the water every 3 days. Until you can get a tank for them they will not survive in your tropical tank. They also will have a hard time eating.