Lumps and ulcers

Hiya, I hope you can help me with a problem. I have a 30 litre tank with a Bristlenose, 2 cherry barbs and 2 guppies. I had an algae problem initially but mostly things have been ok.

For the past few days one of my cherry barbs has been off, and today I noticed that it has what looks like a hole or ulcer on its side. all other fish seem ok.

can someone tell me how I should treat it and what could be causing it? Also will it affect the other fish?

Thanks everyone

How long have you had the fish bloggy? Also did you do the fishless cycle or cycle with fish. Finally, what are your water stats, ammonia etc.

Ok, firstly 30l is not big enough for a bristlenose and this could be leading to a problem as they are messy fish even in a suitable tank.

What filtration do you have?

Sores can be caused by exposure to toxins (eg- ammonia/nitrite) so what are your water stats - readings for ammonia, nitrIte and nitrAte along with Ph will help diagnose any potential problem.

Other causes of sores could be a cut or bite, an infection or parasite - pics would also help.

Hi indi. Ive had the fish for about 7 months . It has an in lid filter with cartridges but I wrap some wool round them and wash that every couple of weeks.

I test the water about once a fortnight. Ammonia is just a bit higher than the 0 level - still yellow but a dark yellow and the nitrite is 0. I change the water twice a week because I know its a small tank.

I am looking to buy a bigger tank in a couplke of months. What size tank would be best for a Bristlenose then? Also, I have some Melafix, would that be any use?

You've just answered your question about the sores with the ammonia reading - chances are the presence of ammonia has either caused or contributed to the sores. Melafix may help but you need to be doing daily water changes until the ammonia is consistently at 0.

How much water do you normally change? In a 30l with a bristlenose I'd recommend 40-50% each time and only wash the filter (in old tank water) if the flow is impeded at all.

The bristlenose will be ok in a 50-60l tank as long as there is excellent filtration but ideally a 70l or larger (smallest I keep mine in is a 2ft long 70l)

60L + for BNs

Where are you located? I know someone selling a great cindition 3ft tank around 130Lish built into stand/cabinet