Anyone seen this before?

[Kwazy]

Hi guys,
Newtank (185 gallons, 35 gallon sump, UV canister filter)

Water= ammonia 0.05!, ntrite 0, ntrate 20, temp 82F, hardness 110, pH 7.2
Fish=1 4" silver arowana, 1 rapheal's catfish

So I woke up this morning to find my baby silver had black pectoral fins. Is this normal? they are a bit more of a grey color now. He is eating and swimming well. It may be the fact I have no light on the tank yet but the fins havent looked like this before.

Thanks

 

[TheRealMacDaddy]

Yes it is normal. They darken up the Pec Fins at night (when the lights are off) so they aren't as visible to predators below them. When you get a light set-up I hope you don't plan on full lighting 24/7. Moon lights are okay, but full day light all the time ain't great, just like total darkness 24/7.

One member left his in the dark for 2 weeks and it freaked out at any light.

But to answer your question yeah, it is normal. As they age, they will eventually stop.

 

[Kwazy]

Cool. Thanks.