Colour change on Sailfin Pleco

[French47]

Hello,

No doubt many of you will have seen this, so please forgive me for asking this question.
I have two Sailfin plecos about the same size 4"long so very young. Today they were laying very close together and one of them had lost all its colour, so much so you could see through its fins. I did think it was dead, until the other Pleco moved away, then its colour came back and he? carried on eating.
Now the question is this a defence mechanism with only its own species or would it do this to any threat?
Once again sorry for asking a question that you all might know, but I am a new to Pleco's.
Cheers

[Barbie]

That color change is definitely a "stress" or submissive reflex reaction. Have you noticed the more colorful one chasing the other? How big is their aquarium? Does it have adequate hiding spots for them both to feel comfortable? Are they getting enough to eat? Those factors can all lead to bullying and potential stress to the subdominant fish in the tank, as you're noticing.

Barbie

[French47]

Hi Barbie, thank you for your reply,
My tank is 100 gallons 5' x 2' x 2' there are 4 caves and lots of holes in the wood, the fish get fed twice a day and the cats get catfish pellets and Algae wafers. I guess this might have been a one off. I hope so, as I have never seen them fighting.

[naturalart]

Just so you know: you dont have to see fighting for there to be domination and stress. One of your sailfins has the upper hand over the other and I'd bet money its the one that didn't change color. Sit and watch and you'll see which pleco defers to the other. Theres your domination and stress. 100g is a good size for a sailfin. As they get bigger the situation could get better or worse depending on the temperament of the 2 fish.

[naturalart]

I'd add some fresh veggies to their diet as well (lettuce leaves, zucchini, squash, peas, potato) it will enhance their health. Nice tank by the way.

[wijnands]

Hi Barbie, thank you for your reply,
My tank is 100 gallons 5' x 2' x 2' there are 4 caves and lots of holes in the wood, .

Looks lovely!

[wijnands]

The original point got me thinking though. I wouldn't be surprised if this mechanism also is present in Ancistrus. My second A. claro is also developing into a male and I'm going to check if I see a colour change when he's near the big male fish.