mollies...harder than platies?

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Aquarium Advice Activist
Sep 5, 2016
I have platies and serape tetra at the moment. PH is 7.5 and stable. I don't use any aquarium salt due to having the tetras and plants that would not fare well with any salt. I liked a couple of large sailfin mollies (they were HUGE - 5" long!) I saw at the LFS, but have read they are far more sickly and tempermental than their livebearer cousins (platies) unless you keep them in brackish water. Without getting a second tank or risk killing my plants and tetras with salt, would mollies be worth a try?
When I kept Sailfins they were in a 55g. I did add some salt, 1TBSP to each 5g.

But if they are kept in full fresh they may do ok. But a 29g might be cramped for them. They are active swimmers.

They hit 6" and if not fed enough greens, they will eat plants. I loved mine, but I catered to them. Mine preferred hard water with a bit of salt.
I have a Dalmatian Molly in my 10 gallon tank. I have a couple neons a platy and zebra danio with it so I don't have any salt in there at all. Aside from being a pig during feedings and eating the plants in there, he is doing great.

Mollies are the most sensitive of all the livebearing fish to changes in their tank water. They require a specific diet that includes a lot of vegetable matter. Like you say, they get big and can be territorial, so small tanks are out for these fish.

Salt can be used with livebearing fish and especially with Mollies. However, if you keep the tank water nitrogen free all the time, which is very challenging, then you can essentially skip the salt.

Mollies aren't a good fish for a beginner, because they're too demanding as far as the water chemistry and diet. Platys and Swordtails are much more tolerant of the water chemistry and will eat most flaked, freeze dried and frozen foods. Keep these instead of the Mollies.

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