Hi I think the hole has happened after death, probably another fish nibbling at it.
You really need a considerably larger tank as 18 litres is much too small for mollies, or any fish reallyand you will be constantly dealing with poor water quality and the problems for fish that brings. Mollies need a 3ft long tank, ideally.
Hi I am new to keeping tropical fish only a few months in. At first I had problems with ammonia levels and lost two fish but managed to get that under control. I have had a few problems with nitrites too but also managed to get that under control. At the minute I have an 18l tank with 2 mollies and 4 very tiny guppy’s. I noticed yesterday that my orange molly developed red blotches on his face but seemed ok still swimming around and eating. Today I have come home from work he was dead, his body had gone very pale and where one of the red blotches were was a hole in its face! Does anyone know if this is due to disease as I am now worried for my other fish in the tank? I apologise for the graphic pic but there is no other way to explain!!!
Unfortunately, the shop has given you very poor advice. I would be looking to either upgrade the tank or rehome at least one of the JDs. Even one with firemouths may be a problem as in that size of tank a mature JD will see all of it as his territory.
Re the jack Dempseys, I’m not sure what to do now that I have them; before choosing what fish to keep I read conflicting advice on the Internet about what would work therefore decided to take the advice from my local fish shop where I bought the tank, I was guided by them who told me these would be ok for my tank ☹️ In fact I’d hoped it would big enough for 3/4 cichlids and was surprised when they said I could put 6/9 in there. They said to stick with 4 first for a week or so to let the filter build up then I could get some more. My original plan was to have 3/4 cichlids, an algae eater and perhaps a few mollys.
Spray bars don't cause pressure on the pump so it's fine to use. Position it how you like, just let it disturb the water surface.
Just another point, but the tank is too small for those fish. A pair of Jack Dempseys need a tank at least 4ft long by 18 inches wide; if you have two males you'll need more space than that. To keep JDs with other cichlids like the firemouths you're looking at a 6 foot by 2 foot to maintain the peace when they all mature.
Hello, New to fish keeping. I have a 30 gallon tank with a Superfish Aquaflow 300 internal filter. I’m not sure what the best position is and whether or not to use the optional spray bar that comes with it. The spray bar seems to reduce the noise but I’ve read it can put unnecessary pressure on the pump - is that true? If I use it, is there a right or wrong way of directing the flow of water? Does there need to be bubbles on the surface? Also, should I turn it up full or not? I have two Jack Dempseys and two Firemouths and I read their natural habitat is slow moving water - does that mean I should turn the filter down?