Three week old 10 gallon fish tank with an odd Dalmatian Molly

[Dalmatian Mollies]

Hello! Three weeks ago I got a ten gallon freshwater tank. Previously I had a 3 gallon tank with two zebra danios which I added to the new tank 24 hours after I set up the tank. The danios are doing wonderful in there new large tank! So we added three female mollies as well as a moss ball and Amazon sword plant. For about a week all the fish were perfectly fine. All were eating and were very active. One Molly, I noticed was a bit more shy than the others and that one died a week after we got it. I removed the body and kept an eye on all the other fish to make sure the rest were healthy. A few days later we went to get another fish as well as a water test to make sure the dead fish didn’t release too much amonia into the water. The water test came back fine except it was a tad bit acidic but not enough to harm a fish. So we got another Molly and introduced him slowly into the tank. Plus we added more plants This Molly seems perfectly healthy except for one weird flaw. She loves to spin when she swims up to the surface. Sometimes I see her swim side ways but I’ve also seen her swim normally. She eats plays with the other fish and explores the tank. I’ve researched a bit about swim bladder and it doesn’t seem to be that. It seems like she does it when she’s playing. Anyone have any suggestions about what it could be? Here is a picture of her.

 

[Dalmatian Mollies]

Hello! Three weeks ago I got a ten gallon freshwater tank. Previously I had a 3 gallon tank with two zebra danios which I added to the new tank 24 hours after I set up the tank. The danios are doing wonderful in there new large tank! So we added three female mollies as well as a moss ball and Amazon sword plant. For about a week all the fish were perfectly fine. All were eating and were very active. One Molly, I noticed was a bit more shy than the others and that one died a week after we got it. I removed the body and kept an eye on all the other fish to make sure the rest were healthy. A few days later we went to get another fish as well as a water test to make sure the dead fish didn’t release too much amonia into the water. The water test came back fine except it was a tad bit acidic but not enough to harm a fish. So we got another Molly and introduced him slowly into the tank. Plus we added more plants This Molly seems perfectly healthy except for one weird flaw. She loves to spin when she swims up to the surface. Sometimes I see her swim side ways but I’ve also seen her swim normally. She eats plays with the other fish and explores the tank. I’ve researched a bit about swim bladder and it doesn’t seem to be that. It seems like she does it when she’s playing. Anyone have any suggestions about what it could be? Here is a picture of her. View attachment 155492

Hello! Three weeks ago I got a ten gallon freshwater tank. Previously I had a 3 gallon tank with two zebra danios which I added to the new tank 24 hours after I set up the tank. The danios are doing wonderful in there new large tank! So we added three female mollies as well as a moss ball and Amazon sword plant. For about a week all the fish were perfectly fine. All were eating and were very active. One Molly, I noticed was a bit more shy than the others and that one died a week after we got it. I removed the body and kept an eye on all the other fish to make sure the rest were healthy. A few days later we went to get another fish as well as a water test to make sure the dead fish didn’t release too much amonia into the water. The water test came back fine except it was a tad bit acidic but not enough to harm a fish. So we got another Molly and introduced him slowly into the tank. Plus we added more plants This Molly seems perfectly healthy except for one weird flaw. She loves to spin when she swims up to the surface. Sometimes I see her swim side ways but I’ve also seen her swim normally. She eats plays with the other fish and explores the tank. I’ve researched a bit about swim bladder and it doesn’t seem to be that. It seems like she does it when she’s playing. Anyone have any suggestions about what it could be? Here is a picture of her. View attachment 155492

Here is a video of her.

 

[Slaphppy7]

Welcome to TFF

You should be testing your own water, get one of these ASAP: https://www.amazon.com/dp/B000255NCI/?tag=ff0d01-20

You also need a good quality water conditioner, get some Seachem Prime, or API Tap Water Conditioner

Is the tank cycled?....read up on cycing here: https://www.fishforums.net/threads/cycle-your-tank-a-complete-guide-for-beginners.475055/

As for the mollie's behavior, not quite sure, could be some sort of swim bladder problem...but get that test kit, test for ammonia, nitrItes, and nitrAtes, and post those results here

 

[Byron]

I suspect there is a water parameter issue here. When you say the water tested a "bit acidic," what exactly was the pH (assuming this was the test)? And what is the GH (general hardness)? The latter you may be able to ascertain from your water authority.

Mollies must have moderately hard water that has a basic pH. This is crucial. Clamped fins (in the photo) and erratic swimming is often the first signs of parameter issues. Some mollies last longer than others under adverse water, but this may well be the issue. The video, short as it is, does suggest this to me.

"Swim bladder" is very commonly used with no actual problem associated with it. What I mean is, rarely do we encounter actual bladder issues, it is much more often something else that has swimming difficult as a symptom. erratic swimming can occur from several internal protozoan (unidentifiable without dissection by a biologist), from sudden/rapid significant lowering of the water temperature, from soft/acidic water, from ammonia/nitrite/high nitrate (esp for mollies), to genetic issues...etc.

Before acquiring more fish, this needs to be resolved obviously but this is also a very small space for mollies or danios, and the latter are shoaling fish that should have a group.