Unusual Behaviour?

I'm new and have a 20l and a 70l tank fish-in cycling. I started with the 20l tank with 2 small platinum mollies one has spots and is a bit bigger. He is the one with odd behaviour. The filter system is above the water level so pours the water in creating bubbles and the molly liked to swim up against the flow and then back down and do it again ..... The smaller just swam around .

As the bigger started bullying I set up the 70l tank and now have put him in there on his own. This tank is a Juwel and has the filter system in a box in the corner so no bubbles - now he spends a lot of his time swimming up and down the corner of the tank - the same corner all the time.

I tried putting a backing on that side of the tank but made no difference.

Is this just an odd fish or is it something that can be or needs to be remedied?

 

Fish know to do that in new environment and tank. As for aggression it is recommended to have 1 male on 3 females so you don't have aggression problems etc. As for swimming in water flow my rasboras do the same thing it's let's say play for them.

 

Thanks appcontrol
I got 2 males to cycle the tank and didn't want females with the breeding problems. Now I have to rethink as I wanted to put a Betta in the small tank. Maybe if I got another male molly when the tanks are cycled would they all be ok in together?

 

Molly's and betta together? Betta is best to keep alone in one tank. And in other bigger you could do some type of community tank, it's on you what you want to mix there. Just do a research before.

 

My idea was put the Betta in the small tank and then the 2 mollies in the bigger tank. As the mollies don't get on maybe another molly would help. Shame as I didn't want 3 mollies

 

My idea was put the Betta in the small tank and then the 2 mollies in the bigger tank. As the mollies don't get on maybe another molly would help. Shame as I didn't want 3 mollies

Try it you can put more than 3 mollys in 70 litters

 

Would adding a different type of fish stop the bigger molly bullying the smaller one or is it a species specific thing?