yo yos fading and fighting? HELP!

[fishface]

i have 3 yo yo loaches in a 25 gallon tank they have been in there for about a month mabe more they have got on well but resently i have notied sometimes 2 of them soft of circle each other then kind of put there mouths on the other ones side or back while this is happening they both go REALLY pale they black colours fade so there just a outline sort of thing its like someones put dust on them or something its hard to explain this goes on for about 2 mins then there black colour returns after a minite or so after that i notied this once in some rocks and again in the middle of the tank are they mating or fighting or is this normal

 

[420Loach]

possibly fighting. my two biggest clown loaches do that to each other if all the shrimp pellets get dropped in the same area when i feed them. they dont seem to hurt each other, but it does look like theyre fighting with each other.

idk if its normal for yoyos, but i know clowns get aggressive whenever foods around. as long as i dont find any loachy corpses then i let them be. they all school after eating anyway, so i figure its all part of being a loach.

 

[fishface]

oh ok ill watch them for a while and keep you updated thanks