Mollies die without salt.

[Manwithnofish]

When I got my first fish about three weeks ago, it included 6 mollies, 5 danios, 1 ruby shark, 1 flying fox, and 3 otos. All six mollies died within 48 hours. People suggested two things. That I use some salt and that I acclimate them gradually. So one week later I bought 6 bigger healthier mollies. I brought them home and put them into my 10 holding tank to which I had added the appropriate amount of Aquarium Salt. I acclimated them to the tank water by floating them in their bag in the tank and every 15 minutes I would add some tank water to the bag. After about 40 minutes or so, I dumped their bag into the tank and they were fine, happy, and had ferocious appetites. I left them in the little tank for a week during which time I did two water changes (20% and 30%) two days apart. I did this to slowly replace the salt water with my tap water. Again, they continued to do very well.

Yesterday, I transferred three of the mollies to my 70 planted tank (with several healthy fish). This morning two of the mollies were dead. Both tanks have my tap water which comes from my well. All water parameters are well within guidelines (Ammonia, Nitrites, & Nitrates all zero). Other than the salt, other differences are filter systems, substrate, plants, light, other fish. Is it salt?

[emc7]

Mollies do like salt, usually they do fine in very hard water also. In soft fresh water, they usually fail to thrive and succumb eventually to some disease. To die suddenly like that, you prob. moved them too fast. Changes in salinity are shocking to some fish.

[Obsidian]

Check your PH in both tanks. A Ph difference can be deadly. Thats what comes to my mind the quickest about this situation. A difference of more than .2 is said to be stressful. Keep in mind that a Ph of 8.0 is 10 times more alkaline than a Ph of 7.0 and you can start to see how this can be a big deal with even a small change. Keep in mind that just because the water has the same source the Ph will not necessarily automatically be the same. I have 3 active tanks, one has a Ph of 6.8 DESPITE a Ph of 8.0 out of the tap. My other two are at 7.6. Because of the huge Ph difference in my one tank with the tap water I have to do small water changes closer together.

[Manwithnofish]

I found this: http://www.fishforums.net/content/Co...ies-Need-Salt/ but I don't want to add salt because I think it will be detrimental to the plants. Mayve I'll just have to not keep mollies.

A Ph difference can be deadly.

I've read that pH can swing widely in a heavily planted tank between day and night as CO2 levels change accordingly. Possibly the culprit. In every case I think the mollies appeared healthy during the day only to be found dead at dawn...hummm. I'll take some pH measurement at different times during the day in the planted tank to see if that's it. Nice tip.

[Ricker]

My mollies for the longest time lived in fresh. Then one day noticed white spots First thing I thought was ICK. I ran to the petstore got some medication for it. Didn't help then I read they like salt. After that their white spots went away and my freshwater tank has never been happier.

[fish_guy]

I use to breed mollies in my pond in front of my house and never added salt to the water.
After 3 months they were breeding so much that I could net out 20+ a week to feed to my lionfish
So I do not think they require salt just hard water like we had in Nashville

[AllmyFish]

I had 3 dalmation mollies in my community freshwater tank, and all of my fish were fine, but the mollies were acting sick. If it weren't for the good health of my other fish, I'd have bet they were poisoned or had an infection. I got my water checked, everything was good except my salt level was really low. I added salt to the tank, and one of the three mollies had a complete recovery, but it was too late for the other two.
Yes, mollies DO REQUIRE salt, and it is good for other fish as well.

[Manwithnofish]

I have Hard water. kH is 7 to 8 and gH is usually around 14 to 15.

And the water in both tanks is from the same source.

I think there is little doubt that the Mollies do better with the salt in the water, but I don't want to add salt to a planted tank, because I'm sure the plants aren't going to like the salt.

[trashion]

These outcomes seem to point to the conclusion: don't keep mollies. Put some other pretty fish in the planted tank

[Manwithnofish]

I know, the mollies all turn their backs and hind when I walk in the lfs. I've gotten enough feedback to come to the conclusion that mollies are not for my freshwater community tank.

So what should I try (or should I start a different thread for this). I have 5 Danios, 1 Ruby Shark, 1 Flying Fox, 1 Clown Pleco, several Otos and so far I still have 4 mollies.

I tend to have hard water, pH around 7.4, I keep the temp between 75 to 79

[Ichthius]

The tank is a 70 gallon? What do ya like?

If you want livebearers, platies look similar to mollies and would work in your tank. They don't breed as prolifically as guppies too.

You can always opt for a school of some sort of tetra as well. You could find out what kind of fish you like the look of, and ask here if they'll work in your tank

[Manwithnofish]

Checked pH every 6 hours and it's holding steady at 7.4. Good news is another molly has survived in the big tank so I now have two (out of 10) in my one tank and two still in the holding tank. Maybe I can transition the last two slower and get them to survive.

As for other fish, I'm thinking about some black skirt tetras or something similar and eventually a few others. Not sure what the "holding" capacity of the tank is. If I go by the one inch per gallon rule, that's 35 fish two inches or less. I probably won't keep that many. That seems like too many fish.

[Obsidian]

You could check the holding tank for salt levels. It is possible there is more salt in there than you think and the transition is too much of a shock. I have not heard of this with salt, only with Ph and temperature, but I imagine it is not out of the question. Also check the Ph of the holding tank. If that is 7.2-7.6 (.2 on either side of your main tanks 7.4) then that is not a likely suspect. If the difference is bigger than this it still may be the culprit.

As for stocking I am starting to look at giant danios. They get to be about 6 inches log and look really nice. I am considering them for my 100 gallon as a cheaper option than the cichlids I was planning. So that is one idea

[doggydad38]

I've noticed that you float our fish and dump them into the tank. Floating only equalizes the water temperature, not the water parameters. It takes me a full 2 hours to acclimate new fish to my tanks before I release them. I pour out all but 1" of the water in the bag, then slowly introduce my water until there is 3/4 of my water to 1/4 of the original water. I then let the bag float for another 30 minutes before releasing the fish. Since I've been doing this, I have lost very few of my new lines. BTW, I have bred Molies in the past with no added salt. They do well as long as the other parameters are in line and also remember that they like slightly higher temperatures. Hope this helps.
Tony

[Manwithnofish]

remember that they like slightly higher temperatures

I keep the temp around 76 to 78 degrees F. What does slightly higher mean?

[JustOneMore20]

Originally Posted by Manwithnofish

I've read that pH can swing widely in a heavily planted tank between day and night as CO2 levels change accordingly. Possibly the culprit. In every case I think the mollies appeared healthy during the day only to be found dead at dawn...hummm. I'll take some pH measurement at different times during the day in the planted tank to see if that's it. Nice tip.

pH swings from co2 (carbonic acid) aren't deadly to fish. pH swings from a changing carbonate hardness (like from loss of buffer (low KH) or by adding something that changes the KH) are deadly. Carbonic acid doesn't affect KH.

I inject pressurized co2 into 3 of my planted tanks during the day. The pH during the day is about 6.2....at night it can rise to around 7, although I've never measured it at night, so it could be higher, since my tap pH if left sitting is closer to 7.4-7.6. My fish don't die..... My KH stays steady....therefore the pH swings don't affect the fish.

Originally Posted by doggydad38

I've noticed that you float our fish and dump them into the tank. Floating only equalizes the water temperature, not the water parameters. It takes me a full 2 hours to acclimate new fish to my tanks before I release them. I pour out all but 1" of the water in the bag, then slowly introduce my water until there is 3/4 of my water to 1/4 of the original water. I then let the bag float for another 30 minutes before releasing the fish. Since I've been doing this, I have lost very few of my new lines.

I agree. Just floating only gets the temp closer to yours. It does nothing for water parameters, including pH, which could be alot different from the store's. When I add new fish to my non co2 injected tanks, I float the bag for awhile after pouring out most of the store's water and then add in water from my tank in 30min incremates (sp?), like you do doggydad. I do this for about an hour and a half before releasing the fish. In co2 injected tanks, I drip acclimate all fish for about 2 hours.....only because the co2 levels are so high and the fish aren't used to that.


FYI, I wouldn't use the inch per gallon rule.....its not a great one IMO.


You have alot of options for a 70g tank. If you are going to keep the Danios, I suggest getting atleast 4 more of them. You have the room, so atleast make the little guys a bit happier by adding to their group.

As for the Ruby shark, is it a Red-line Torpedo Barb/Denison's Barb? If so, they are shoaling, meaning you'll want to get atleast 5 more of them to make them happy.

After that, you could look into a shoal of Cories for the bottom, or some peaceful loaches and maybe a pair or 2 of dwarf Cichlids.

[Manwithnofish]

Carbon dioxide dissolved in water is in equilibrium with carbonic acid:

CO2 + H2O ⇌ H2CO3

Just to be sure we're talking about the same thing. I'm not sure I agree with the statement, but at any rate, I checked my pH every 6 hours around the clock and it measured 7.4 every time. So, that's not the issue. Acclimation is looking like the issue. I did do it more slowly each time.

As for the acclimating process, I did slowly add water from the receiving tank into the bag as it was floating. I currently have 3 surviving mollies in the 70 gal. tank and found one fry in the 10 gal tank (all by itself). Will have to find something to feed it.

The Ruby Shark is I believe Epalzeorhynchos frenatum

[doggydad38]

I usually keep my mollies at 78 to 82 degrees. They do well at lower temps, but seem to do better once the temperature reaches the lower 80's.
Tony

[trashion]

Denisonii barbs are absolutely gorgeous! A LFS near me has a shoal in a display tank, I love the way they look.