Mollie-Clamped Fins

[Just Add Water]

Tank 10 gal
5 months old
3 Mollies
3 Otocinclus
1 nerite snail
I did a 30% water change yesterday. Today my male Mollie is clamping his top fin. Still swimming, eating and chasing the girls.
Nitrate 20
Nitrite .5
Ammonia 0
PH 7.8

 

[CaptainBarnicles]

Are you using strips or liquid to test? Your Nitrite should be reading 0...so if the test is accurate that might be your problem

 

[Just Add Water]

Test strips

 

[emeraldking]

Male sailfin mollies don't flare all the time with their dorsal. If it's only his dorsal he should be okay.
But what's the gH? For I don't see that mentioned.

 

[Back in the fold]

Add salt . Mollies like a little salt. Four teaspoons per ten gallons. Replace proportional amount at each water change , don’t let it build up to more than the four teaspoons per ten gallons concentration.

 

[Just Add Water]

I added some API QuickStart about 2 hrs ago. Bought a new bottle of API test strips. New readings:
GH 120
KH 180
PH 7.8
Nitrate 0
Nitrite 0
I need to get another bag of pool salt for my pool. Did I read somewhere that pool salt is ok for the aquarium?

 

[Colin_T]

The GH is fine for Otocinclus catfish but is too low for mollies and needs to be around 250+ppm for the mollies. Your Otocinclus won't do well in harder water.

Swimming pool salt is rock salt and is normally fine to use in their tank. However, you have Otocinclus catfish in the tank and they don't want salt. Ideally you want a separate tank for the mollies so they can have hard water, and another tank for the Otocinclus so they can have soft water.

 

[Byron]

I concur. A GH of 120 ppm [= 6 dH] is soft water (to use a subjective term) and no where near what mollies must have to function long-term. A 10g is too small a space for mollies anyway (assuming they were OK with the water and grew, which they won't) so now is the time to re-home the mollies and think of suitable soft water fish. There are a number of nano species, so named because they are small, that cold live quite well in a 10g.

On the salt, it does not raise GH, and is not the answer here as it will not solve the lack of calcium especially involved with GH.

 

[Just Add Water]

Thanks for the info Colin_T and Byron.
I’m happy to report that after adding the QuickStart the Nitrates fell to 0 and within 48 hours he was swimming normal with no more fin clamp.

 

[10 Tanks]

Hello. If you research the history of keeping Livebearing fish, you'll learn that Mollies are by far the most demanding of pure water conditions of any of the other Livebearing species. So, a small tank that's subject to ups and downs in the water chemistry is no place for Mollies. They must have large, and very frequent water changes because they can't tolerate even a trace of nitrate in their tank water. Even short time exposure to nitrate will affect their immune system and bacteria that lives in all tanks can infect them. Hopefully, the bacteria starter has limited the damage to your fish. In the future, if you're determined to keep Mollies, you might consider a much larger tank. At least 30 gallons and just keep a few. The more water you have, the less likely your fish will experience poor water conditions.

10 Tanks (Now 11)

 

[Essjay]

I'm afraid there are still issues for mollies - the hardness and the tank size. These fish must have water much harder than the level you reported in post #6 - they need around 250 ppm GH - and a tank at least 36 inches long. Mollies are big fish. Both the hardness and small tank are likely to be causing stress to the molly and stress lowers their immune systems allowing the fish to become sick more easily.

 

[Just Add Water]

Thanks for the great info. I’ll make plans to take them to my LFS and purchase something more suitable for my tank size and parameters. What fish would you recommend in a 10g with my otocinclus?

 

[Byron]

Thanks for the great info. I’ll make plans to take them to my LFS and purchase something more suitable for my tank size and parameters. What fish would you recommend in a 10g with my otocinclus?

Taking the parameters posted in post #6, namely
GH 120ppm [assume this is in ppm, as dG would b beyond probable] which equates with 7 dH
KH 180ppm (10 dKH)
PH 7.8
and given the tank is a 10g and has plants (in the photo)...you have good options. "Nano" fish are best, they do not get large and you can have a good number of them to provide interest. Some examples:
Ember Tetras (Hyphessobrycon amandae)
Chili rasboras (Boraras brigittae)
Rocket pencilfish (Nanostomus eques) which live at the surface and do not swim much so a good upper level interest, but this is the only pencilfish for a 10g.
Pygmy cories (Corydoras pygmaeus) or salt and pepper cory (Corydoras habrosus--not to be confused with the pepper cory) but only if you have sand for the substrate.

If you have gravel, sand is well worth considering as it opens up possibilities for substrate fish. And now is the time to change substrates, when you return the mollies, but do not get any fish until you work out just what you want.

 

[10 Tanks]

Thanks for the great info. I’ll make plans to take them to my LFS and purchase something more suitable for my tank size and parameters. What fish would you recommend in a 10g with my otocinclus?

Hello. Whatever you decide on, you can't have very many of really anything. With just 10 gallons of water, you'll need to change half the water at least of couple of times a week, to maintain livable conditions. Any pet store that cares anything about the health of the fish they sell will recommend a much larger tank.

10 Tanks (Now 11)

 

[Just Add Water]

Taking the parameters posted in post #6, namely
GH 120ppm [assume this is in ppm, as dG would b beyond probable] which equates with 7 dH
KH 180ppm (10 dKH)
PH 7.8
and given the tank is a 10g and has plants (in the photo)...you have good options. "Nano" fish are best, they do not get large and you can have a good number of them to provide interest. Some examples:
Ember Tetras (Hyphessobrycon amandae)
Chili rasboras (Boraras brigittae)
Rocket pencilfish (Nanostomus eques) which live at the surface and do not swim much so a good upper level interest, but this is the only pencilfish for a 10g.
Pygmy cories (Corydoras pygmaeus) or salt and pepper cory (Corydoras habrosus--not to be confused with the pepper cory) but only if you have sand for the substrate.

If you have gravel, sand is well worth considering as it opens up possibilities for substrate fish. And now is the time to change substrates, when you return the mollies, but do not get any fish until you work out just what you want.

Thank you Byron. I do have sand and a lot of live plants.