Weird scratching behaviour

[cokecowboy70]

I have a newly bought colony of maingano which I believe are 6 males and 14 females. They range in size from 6 to 9 cm in length.

I have noticed them scratching in the past so I cleaned the tank and water and filters and have the system quite clean now.

But now I notice weird behaviour. There are four broken pots that they hide in which are close together. Most of the fish hang out in this area. They are exhibiting this scratching behaviour on the glass bottom of the tank. They appear to scratch once and fly a few inches into the air.

Just beyond this area is a piece of driftwood where other maingano rest. They are doing nothing. No scratching behaviour at all. Even when the fish move around the tank, only those between the pots scratch and those near the driftwood do nothing. When the fish from the pot area change places with those at the driftwood, they stop the scratching behaviour.

If I had never kept this type of fish before I would say they are dancing or competing for position in the group.

They haven't started breeding yet. There is only slight male chasing and defence.

It is totally bizarre to watch fish scratch in one area and to the left of that about 1 foot there are the same type of fish doing nothing at all.

P.S. They are only scratching off the glass bottom. Not off the pots or any other structure.

Does anyone have any advice other than dirty water and parasites?

[Priscacara]

Apart from the water conditions and parasites my only other guess would be a bit of stress from the move in which case it should settle down quickly. Possibly a bit of a flare up of parasites due to the new environment would be where I would point the finger but I'm new to the hobby and could be way off the mark.

[Maskedman]

Very wierd. If the scratching is always localised around the pots, then they may be the problem. Replace them with something else & see if it makes a difference. Put a substrate in there too. Maingano love to dig & they may be trying dig holes, though they usually use thier mouths for that.

If it's a paracite or some other nasty, then it should affect all of the fish. Maybe not to the same degree & maybe not at the same time, but it should affect them all.

They might not like this cleaning out your filter either. If you REALLY cleaned it & you have no substrate, you have virtually no bacteria population to break down fish wastes. So it would be like cycling a brand new tank. Ammonia peaks etc. That will certainly stress the fish enough to make them do wierd things. Maybe you can put a filter in from another tank (disease free) if you have one. Or perhaps some used substrate from a friends tank? I think the cleaning could well be the problem. Get some substrate in there so that next time you clean your filter you don't lose your beneficial bacteria colony. Your fish will love you for it.