Not 100% sure, But I think it's heater burn.. :/

[moxxommox]

This has been on my sailfin for the past week, i've put in stress coat and he's purked up alot! he's eating and being normal... I don't know if it's getting better, Someone moved my heaters and they were on 27 degree C .... The tank was up to 29.6 degree C and I think it's burnt the little guy cos it was there over night..

can any one suggest any other things?

 

[Horiyoshi III]

Looks EXACTLY like heater burn,for some reason they either like to wedged between it and the glass or just lay on it.And,hes gonna have a mark on his belly for life,mine did at least.

 

[davo]

They probably like to be wedged because they feel most secure, and they often find themselves there when they have no where else to hide (and sometimes when they have better places). Unlucky, was a nice looking gibby. Get a heater guard or make one.

 

[johnptc]

you could put a little bio-bandage on it... would not hurt might help

 

[Tokis-Phoenix]

Although it looks bad, the fish will heal- i've seen pleco's with worse heater injuries and recover from them. Just do lots of small regular water changes using StressCoat dechlorinator and some Melafix and the pleco will heal up fine .
What do you feed the sailfins at the moment and how often and much on average?

 

[davo]

Mine get prawns, cucumber, zucchini, potatoes, shrimp, krill, tablet food- both carnivore and spirulina based, worms of different sorts, sweet potato... the list could go on. As to how much, mine get fed pretty much every day, but i have a lot of plecos, so i feed quite a lot, but it is gone quickly and everyone gets a share of the food. Check the dietry thread too for more info and food ideas.

 

[loach43]

ouch! I'm also in belief that the damage will nearly if not completely subside.
Plecos heal up really fast especially if you up the water changes on them a bit.