Siamese fighter!!!

Help I have just put some new fish in my sons tropical 21l tank. 4 mollies and my Male Siamese is going after my male Molly and won't leave him alone!

I don't wanna come down to a dead Molly in the morning.

Tank is 0/0/10-15

I am having nightmares with my fish at the moment. Thanks in advance

 

Bettas are aggressive and territorial. They do best in tanks by themselves. Anything similar in size or shape to them with bright colours or long fins is often a target. I would suggest separating them. A 5.5 gallon tank for just the betta would be my suggestion.

 

The Molly he is after is all black the others are

1) Dalmatian Molly.
1) orange
1) white
1) black

Is he going to kill all my fish?

 

Yes. And if he doesn't, having 4 mollies in a 21 liter tank will. You need to take the mollies back or get a bigger tank for them (80 liters or more would be my suggestion).

 

Bettas do best alone. You've got too many fish in a small space, this can really bring out the aggression.

 

The betta is acting out. He is trying to find his own territory and can't. The tank is just too crowded. I've kept a betta in with my mollies for the longest of time. The only difference is that he had more than enough room in the 30gal to create his own territory, so there was no fighting. I would suggest that if you want your fish to peacefully coexist, get a bigger tank. Or, if you can, return the mollies. The tank that you have is perfect size for 1 betta.

If you keep the fish all in that tank, what will most likely happen is your betta will kill that molly, and then will pick on another one, kill it, and so on until he thinks that he has a good-sized territory for himself.

 

Keep in mind that not all Betta's are cut out for having tank mates even with a larger tank. It all depends on the individual Betta's temperment.

 

Keep in mind that not all Betta's are cut out for having tank mates even with a larger tank. It all depends on the individual Betta's temperment.

Quite true, there are just some out there who, for happiness and health, just need to be left alone. I myself have had the best of luck with bettas and have never truly gotten a vicious betta. They've always been able to have tank mates with them, when the tank size was right

 

a single betta is an awesome pet for a little boy, and far more interesting for a young'un than the mollies....or at least so says my son, who still is trying to persuade me we have room for another tank for him to have a betta!

 

I as well think you should separate them. I would get a larger tank for the mollies and leave the betta in this one but alone. I have two male betta in a divided 10 gallon tank and love them to pieces.

 

If you could get rid of the mollys, you could maybe add a few corydoras. Bettas are not normally aggressive towards them.

 

In a tank that size, the betta will most likely be aggressive toward ANY fish. I'd recommend letting him live alone.

 

Right, the Betta has now calmed down & seems to have found its territory in a cave... They all seem to have calmed to to be fair.

Thank you for all your advice, I think I will see how they get on over the weekend & if it's no better or worse I will take the Mollies back.

I am honestly hoping that the Betta was just being aggressive as he was litterally just put in the tank, along with the trauma of being transported.

Maybe that's just wishful thinking but my local aquatics store is very good and knew exactly what set up I had got & what fish were in situ already. Surely they wouldn't sell me fish knowing that they wouldn't be compatible in the tank?

 

Not on purpose. Sometimes they just really don't know...

 

Right, the Betta has now calmed down & seems to have found its territory in a cave... They all seem to have calmed to to be fair.

Thank you for all your advice, I think I will see how they get on over the weekend & if it's no better or worse I will take the Mollies back.

I am honestly hoping that the Betta was just being aggressive as he was litterally just put in the tank, along with the trauma of being transported.

Maybe that's just wishful thinking but my local aquatics store is very good and knew exactly what set up I had got & what fish were in situ already. Surely they wouldn't sell me fish knowing that they wouldn't be compatible in the tank?

It is a sad but true fact most fish stores encourage their employees to sell sell sell and well tell you that one species and another well get along just to make a sale.

 

It is a sad but true fact most fish stores encourage their employees to sell sell sell and well tell you that one species and another well get along just to make a sale.

Awww I hope not this one, it's a family business and 3 generations work there...

He even came out to my other tank & sorted out my goldfish. which I thought was very generous of them.

 

I would suggest you watch them very closely just in case, and it would be best, even if there aren't any more upsets, to at least look for a bigger tank to put the mollies in at one point. The rule 1in of fish=1gal really should be applied. It makes for happier, healthier fish.

 

The mimimum recommended tank size for Mollies is 20 gallons (approx 80l). The reasons for this minimum tank size it that Mollies are very active fish and need at least that much horizontal swim space. Also, Mollies are huge waste producers and it will be very difficult to keep your ammonia/nitrite levels at 0ppm. And even on the off chance that you can keep ammonia/nitrite at 0ppm, your nitrates will be going thru the roof since the more ammonia that is produced, the more the resultant nitrate.