Mollies (behavior & salt?)

[supermazz9]

I just went out and picked up 2 silver mollies and 1 mixed mollie. Now that I brought them home, it occurs to me that they like to be salted.

What kind of impact will salt have on the rest of my tank (planted, assorted tetras [emperors, serpaes, buenoes ares, glowlight], platys, pleco, and frogs).

Conversely, what impact will no salt likely have on the mollies?

Also, are mollies generally aggressive? The 2 silver mollies seem to be territorial and attack each other and any other fish that wander into "their" turf.

[TCTFish]

Mollies can live fine without salt. Your other fish wouldn't like it very much, though a small amount (tablespoon per 10 to 15 gallons) wouldn't hurt.

Salt does seem to have some type of influence to aggressive behavior in brackish fish. Less salt generally means a meaner attitude. This may have something to do with the fact many of these fish wander into fresher water to spawn; thus perhaps having an impact on the animal's hormonal trigger responses to the spawning environment.

Mollies in general can be very pushy fish and mostly the males. It is very common for male livebearers to be aggressive toward other male livebearers of ANY livebearing species. Just needs to be a livebearer. Best to have a higher ratio of females than males (at least three females to one male). Sailfin mollies seem to be the most aggressive of the mollies.

[Fishyfanatic]

There is no need for salt with mollies unless they are wild caught. They have been bred for many generations in freshwater tanks that they do not require it. The pleco would not fare well with it anyhow.

[Zagz]

I'd have to agree that salt with mollies isn't necessary unless wild caught. I have several mollies in different tanks with no salt. I've had some over a year now.

[Jaybird]

I would have to agree with TCTFish about the sailfin molly aggression. I had an orange sailfin and he was a bit aggressive, but he was nothing compared to the dalmatian sailfin I recently got. There were two orange females for the orange male and three black females for the dalmatian. It seems that the dalmatian did not like the colour orange and attacked them whenever he saw them. He stressed the orange mollies so much that they ended up with some major problems and died. Now he is just aggressive when there is food about.