I Need Help With My 2 Mollies

[NorthPoleFish]

Back in November 2023, I set up my son's 3 gal cylinder fish tank and stocked it with too many fish. I didn't know any better being new to the hobby. After several fish dying, we ended up with 1 female blue platty and 3 male mollies (can't remember the types) that are still alive. For the 3 gal tank, it ended up doing the nitrogen cycle with fish in it. The 3 gal tank has been happy for months now, with no problems, the fish living in it is another story. After posting on another fish forum, I was told I had way too many fish in the 3 gal tank and that is why one of the mollies kept sinking and not swimming right. Up to this point, which would have been the beginning of June 2024, I was only changing the water every week or so. I started doing daily water changes of 1/3 of the water and the red molly started doing much better and would swim around and was eating just fine. I bought a 20 gal tank around this time and had it go through the nitrogen cycle with no fish and the nitrogen cycle is complete and the platty and mollies are now in the 20 gal tank. I understand now that the red molly was very stressed being in such a small tank for so long. I was hoping that being in a bigger tank would help, but he hasn't changed at all. The fish have been in the adult tank for about 3 days now (I know that isn't a long time) and I fasted all the fish for 3 days. The 3 gal tank is now home to 6 fry that the platty had.

The red molly that is sick and really stressed was doing better (and still alive) up until Wednesday, July 3. Up to this point, I was changing about 1/3 of the water every day and I believe that made a big difference for the red molly. I went out of town on Monday, July 1 for a week. I did a water changed and vacuumed the gravel before I left (there was a bit of fish poo and uneaten food). It was 2 days later when my friend came over to change the water (she changed the water on July 3) and the red molly was sitting on the bottom of the tank, alive, but not moving. And the red molly has been that way since. My friend came over every day after that while I was gone and did a water change, about 1/3 of the water. My friend also feed the fish every other day. He can swim, sort of, but mostly just sinks to the bottom of the tank. His left pectoral fin rapidly moves and he opens and closes his mouth all the time. This little fish is quit the tough guy to be hanging in there like this (he has been sick for about a month now like this) and would like to help him get better if it is in my power to do so. I'm new at this, but I'm learning.

Is there anything that I can do for him? I know it is hard to tell with fish what the problems are, which is why I'm asking since maybe someone else had a similar problem. Is this a wait and see what happens/how the fish is doing after a couple days and then go from there? I fasted all the fish and gave the red molly and the golden molly an epsom salt bath this morning and tried feeding them a cooked, skinned pea. The epsom salt bath was 1 tablespoon per gallon of water for 10 minutes and then 1/4 tablespoon of espom salt per gallon of water for 5 minutes and then back into the 20 gal tank. Neither fish wanted anything to do with the pea. Fasting didn't make any difference in either conditions of the either sick fish. So far, the epsom salt bath doesn't seem like it has made a difference either. I was wondering if I could give them another epsom salt bath later today or tomorrow? I have read online that twice a day for extreme cases can be beneficial and even leaving the fish in a low concentrated epsom salt bath overnight can help. I am wondering if both sick mollies have a swim bladder problem which is why I've done the fasting, epsom salt baths, and trying to feed peas. I'm pretty sure the golden molly has a swim bladder issue since he was fine, swimming normally, until yesterday morning when he is now upside down.

I tested the 20 gal tank this morning:
Ammonia = 0ppm
Nitrites = 0ppm
Nitrates = 5 ppm
High pH = 7.8
kH = 11 dKH
gH = 6 dGH (although I'm not 100% sure on this one, I used a Sera test and according to the directions, you add one drop of solution to 5 ml of tank water and swirl after each drop, waiting for the color to go from red to brown to eventual green, never got red and it was a green hue about 4 drops in)
I changed about 20% of the water on July 8 to try and get some of the old fish food (from trying to start the nitrogen cycle) cleaned up.

For the first couple months, I only feed the fish Fluval Bug Bites flakes. They now get a variety of food that includes Hikari micro wafers (slowly-sinking), Hikari micro pellets (semi-floating), Hikari algae wafers, and I recently introduced freeze-dried bloodworms. After a lot of trial and error to figure out how much to feed the fish (I know I was overfeeding them for a number of weeks now), I now only feed once a day and generally two small pinches of flakes and one of the other foods. Could the problem with the red molly be a food related issue? Should I be feeding the mollies and platy something else or anything in addition to what I am already feeding?

I am starting to wonder if I need to think about euthanizing the red molly at this point since I don't want him to suffer any more than he has. I was hoping he would hang in there to get better, but now I'm hoping he will pass away on his own since I don't know if anything can be do to save him. I'm hoping that I can still save the golden molly.

 

[Essjay]

gH = 6 dGH (although I'm not 100% sure on this one, I used a Sera test and according to the directions, you add one drop of solution to 5 ml of tank water and swirl after each drop, waiting for the color to go from red to brown to eventual green, never got red and it was a green hue about 4 drops in)

You have soft water which is the problem for the molly - they need hard water to do well, and often become sick in soft water. Platies also need hard water though they can cope with it a bit softer than mollies.

Are you on mains water, and if you are does your water provider's website list your hardness (GH)? If they do and the number they give is similar to your tester, you really do have soft water.



Do you have only mollies and platies, or are there other fish in the tank as well? If it's just those fish you can make the water harder for them by adding minerals such as Rift Lake salts to the tank. American members should be able to suggest brand available there.
You would dissolve the salts in a bucket of water outside the tank when refilling after a water change rather than add the salts directly to the tank, and start by doing a small water change every couple of days to slowly increase the GH in the tank as large changes are not good for fish.

 

[Ichthys]

As @Essjay has already said, the soft water is the problem. Mollies simply cannot survive in soft water.

 

[AdoraBelle Dearheart]

Agree that mollies thrive in harder, and often brackish, water - I would go for adding aquarium salt to the tank water itself rather than epsom salt baths if you only have mollies and platies.. and the rift lake cichlid salts for raising the GH if these fish survive and you want to continue keeping livebearers for the future...


However, I'm really sorry, but I'm not optimistic about the chances of survival for the two mollies in the photos, I'm sorry The red is an especially pretty colour, and I know it's tough when you're new, finding things going wrong and have been making big strides to try to fix things, and he's held in there for so long. I'll cross fingers and fins that they do pull through.

But should they not make it, I do want you to give yourself credit for realising where you'd made mistakes and working to try to fix them. A 20g rectangular tank is much, much better for fish, and a good size for a first tank. So I'd just want to suggest that especially if you wind up losing these two, you would have a much easier time of things (and a much greater choice in fish species you can keep!) if rather than fighting to harden the water you naturally have from the tap in order to keep livebearers, but you instead restock with softer water in mind, and choose fish that will thrive in the water you naturally have, you know?

Wishing you the best of luck whichever way, people will be more than happy to make suggestions or give further advice any time you might want! It's generally a very helpful and welcoming forum.

 

[NorthPoleFish]

You have soft water which is the problem for the molly - they need hard water to do well, and often become sick in soft water. Platies also need hard water though they can cope with it a bit softer than mollies.

Are you on mains water, and if you are does your water provider's website list your hardness (GH)? If they do and the number they give is similar to your tester, you really do have soft water.



Do you have only mollies and platies, or are there other fish in the tank as well? If it's just those fish you can make the water harder for them by adding minerals such as Rift Lake salts to the tank. American members should be able to suggest brand available there.
You would dissolve the salts in a bucket of water outside the tank when refilling after a water change rather than add the salts directly to the tank, and start by doing a small water change every couple of days to slowly increase the GH in the tank as large changes are not good for fish.

I have figured out my water hardness problems. I having been using the wrong water to fill the tanks. We have well water with a water softener and that is the water that I've been using. I made a huge mistake (for reasons unknown) in which water to put in the tanks. I need to use the non-softened water that is out drinking water.

I did a GH test and that water is 12 - 13 dGH. I know this will be a huge improvement in the water quality for the fish. Probably won't help the two sick ones, but should help the other molly and platy. I plan on doing water changes with the right water over the next few days and see how things go. Going to do a 25% water change every day.

Quick question, will mollies and platies do well with 12 - 13 dGH water, or do I still need to make it harder? Thanks for your help.

 

[NorthPoleFish]

Agree that mollies thrive in harder, and often brackish, water - I would go for adding aquarium salt to the tank water itself rather than epsom salt baths if you only have mollies and platies.. and the rift lake cichlid salts for raising the GH if these fish survive and you want to continue keeping livebearers for the future...


However, I'm really sorry, but I'm not optimistic about the chances of survival for the two mollies in the photos, I'm sorry The red is an especially pretty colour, and I know it's tough when you're new, finding things going wrong and have been making big strides to try to fix things, and he's held in there for so long. I'll cross fingers and fins that they do pull through.

But should they not make it, I do want you to give yourself credit for realising where you'd made mistakes and working to try to fix them. A 20g rectangular tank is much, much better for fish, and a good size for a first tank. So I'd just want to suggest that especially if you wind up losing these two, you would have a much easier time of things (and a much greater choice in fish species you can keep!) if rather than fighting to harden the water you naturally have from the tap in order to keep livebearers, but you instead restock with softer water in mind, and choose fish that will thrive in the water you naturally have, you know?

Wishing you the best of luck whichever way, people will be more than happy to make suggestions or give further advice any time you might want! It's generally a very helpful and welcoming forum.

I know mollies live in brackish water and can't believe I was using the wrong water.

I'm not optimistic about the chances of the 2 sick mollies to survive either and that is ok. While I do not like creatures in my care to suffer at my mistakes, as you said, I'm learning and trying to fix them so that future fish have a much better chance of surviving.

Quick question though, what other fish species besides mollies and platies, like brackish water? I have a bit of research to do on that, but am wondering for future stocking options since I'm sure that will be an option here at some point.

Thank you for all your help. The people on this forum have been very helpful.

 

[NorthPoleFish]

Will give an update on how all fish are doing once I get the water hardness levels up.

 

[Essjay]

Actually mollies don't need salt water though they can survive in it. And platies won't appreciate any salt. What mollies need is hard water, preferably a minimum of 250 ppm/14 dH, so your unsoftened well water would be OK for them.

As a general rule, salt should only be used in fresh water tanks as a mild disease treatment; it should not be added routinely.





As a side issue, using the softened water and keeping soft water fish isn't a good idea either if the softener is the salt type. It's better to keep hard water fish in water that's not been through the softener.

 

[NorthPoleFish]

Actually mollies don't need salt water though they can survive in it. And platies won't appreciate any salt. What mollies need is hard water, preferably a minimum of 250 ppm/14 dH, so your unsoftened well water would be OK for them.

As a general rule, salt should only be used in fresh water tanks as a mild disease treatment; it should not be added routinely.





As a side issue, using the softened water and keeping soft water fish isn't a good idea either if the softener is the salt type. It's better to keep hard water fish in water that's not been through the softener.

Thank you for clearing that up for me that it isn't so much the salinity of the water that matters, but the hardness of the water for mollies and platies.

I think I'll just keep hard water fish since my softened water is the salt kind. Will just make things easier for everyone.