Just wondering if those micro organism or rather those slimy stuff that we usually find on the side of the tanks harmful to ABN fry? Hv read varying views on that, some says its harmful, while others say those were what the plecos like eating. So, are they good or bad, really, in your opinion? If they are bad, I will have to make an effort to manually scrub the sides of tank regularly.

is it the brown stuff?

its a bit of a double edged sword im afraid. They do eat it but if it builds up too much it can kill the fry. thats why people use grave lin breeding tanks, to stop it building up too much.

piccys?

brown stuff in the tank is usually brown algae, which is symptomatic of a new or unstable tank. once the water stabelises it usually goes away

the sort of translusent slime that eventually covers everything in the tank is a good thing, thats all the good bacteria de-toxifing the water for you. only thing is they can get to numerous and then they need something else to feed on as the ammonia etc in the water becomes too little...enter your bristlenose fry with their soft bellys resting on the bed of algae.

gravel stops this, not terribly sure why but at a guess i would say that as the fry are moving across the gravel it acts as a cleaner for their belly. or maybe there is just less on the gravel.

Thanks Doug for clarifying. So that brown stuff is brown algae, are they harmful? and the transluscent slime is safe, thanks.

only visually