Sailfin

[gn3ric]

hi i have 2 sailfins and for some reason one of them is quite agressive. He likes to chase all the female but when the other sailfin comes in he chases him away and he actually beat him up. That night i went to sleep next morning i woke up he's dead. i saw some bit marks, i think it was from him. Should i seperate him?

 

[gizzmo1979]

I had that problem with my Sailfin. I did seperate it and put it in a tank with other agerssive fish for about 2 months and sure has cured the problem now it is back in the tank with my platys, guppies, zebras and sword. Have not had any problems.

 

[gn3ric]

i also have a sword tail a black dalmation one and the sailfin didn't even bother him kinda weird..

 

[nmonks]

What size tank do you have? What is the ratio of male mollies to females? Are you keeping them in fresh or salty water?

Sailfin mollies are big. Adult females can be up to 15 cm long, which means you need a tank at least 100 cm long (3 feet) to keep them comfortably. If you think that's a lot, it's only ~6 times longer than they get. So not that big. If the tank is too small, they can't "spread out" when one fish is stressing another, and that forces them to fight. Think cats in a cage.

Adding plants (live or plastic) helps by breaking up the line of sight. The more places a fish can hide, the calmer the tank will be.

Male mollies should be outnumbered 2-3 times, at least, by the females. In a tank only 100 cm long, and you only have space for a few mollies, best keep only one male. Multiple males work best in large tanks and where you have lots of fish. It's the same with my halfbeaks: keep 2 males, and they will literally fight to the death. Keep 10, and they get along fine.

Molly males fight over females, just like guppies and platies, but being bigger, the fights are more dramatic and potentially harmful. It isn't being psychotic, so putting it in a "sin bin" aquarium with aggressive fish isn't really a solution, and potentially aggressive fish like cichlids or pufferfish will simply demolish the poor molly. Simply keep the male molly in a big enough tank with just females.

Behavioural problems with fish are 95% of the time because we, the aquarist, force fish into situations they haven't evolved for. We expect territorial cichlids to get along in tiny tanks, or male mollies to share females peacefully. That's our fault, not the fish's.

Bite marks on your dead fish are unlikely to be from the molly. They don't really have biting teeth, instead being adapted to eat algae. Most fish peck at corpses in the tank, and in doing so will damage the skin of the dead fish, producing things that look like bites.

Make sure you add salt to the water. Mysterious molly deaths are usually prevented by keeping them in brackish water. Salty water also inhibits fungal and bacterial infections, so and damage gets repaired quickly and harmlessly. Swordtails, platies, and guppies are fine with a little salt, though they don't need it. You don't need much salt: around 3-5 grammes of marine mix per litre is plenty.

Cheers,

Neale

 

[gn3ric]

What size tank do you have? What is the ratio of male mollies to females? Are you keeping them in fresh or salty water?

Sailfin mollies are big. Adult females can be up to 15 cm long, which means you need a tank at least 100 cm long (3 feet) to keep them comfortably. If you think that's a lot, it's only ~6 times longer than they get. So not that big. If the tank is too small, they can't "spread out" when one fish is stressing another, and that forces them to fight. Think cats in a cage.

Adding plants (live or plastic) helps by breaking up the line of sight. The more places a fish can hide, the calmer the tank will be.

Male mollies should be outnumbered 2-3 times, at least, by the females. In a tank only 100 cm long, and you only have space for a few mollies, best keep only one male. Multiple males work best in large tanks and where you have lots of fish. It's the same with my halfbeaks: keep 2 males, and they will literally fight to the death. Keep 10, and they get along fine.

Molly males fight over females, just like guppies and platies, but being bigger, the fights are more dramatic and potentially harmful. It isn't being psychotic, so putting it in a "sin bin" aquarium with aggressive fish isn't really a solution, and potentially aggressive fish like cichlids or pufferfish will simply demolish the poor molly. Simply keep the male molly in a big enough tank with just females.

Behavioural problems with fish are 95% of the time because we, the aquarist, force fish into situations they haven't evolved for. We expect territorial cichlids to get along in tiny tanks, or male mollies to share females peacefully. That's our fault, not the fish's.

Bite marks on your dead fish are unlikely to be from the molly. They don't really have biting teeth, instead being adapted to eat algae. Most fish peck at corpses in the tank, and in doing so will damage the skin of the dead fish, producing things that look like bites.

Make sure you add salt to the water. Mysterious molly deaths are usually prevented by keeping them in brackish water. Salty water also inhibits fungal and bacterial infections, so and damage gets repaired quickly and harmlessly. Swordtails, platies, and guppies are fine with a little salt, though they don't need it. You don't need much salt: around 3-5 grammes of marine mix per litre is plenty.

Cheers,

Neale

Yes i have been adding salt in every time i do a water change. i use to have plants but i took them out because i was deciding on changing my rocks. i did section by section so i don't put all the fish into a big shock so eveverything went well until now. About my tank, i have a 20 gallon tank and filters are running good and adding salt once every day or so. im not sure on how my sailfin exactly died. i didn't do any water change yet, i've been feeding them brime shrimp im not sure that is the case or not. In my 20 gallon tank i have about 4 female mollys, 1 dalmation swordtail, pleco, and 2 corys. i use to have 2 males until the other sailfin male died. thank you Neale for the reply hope to get another one soon THANKS!