Rosy barb confusion

[Samdaman]

I had a huge axolotl but it passed away about two months ago I have a pond in my backyard(just a cattle trough in the ground) and I put about 25 feeders in it because I didn't what to kill them then the other day when I was doing a clean out I saw all the feeders have changed from a dull brown to a red(pictures attached) I'm confused because I thought that barbs where tropical a but they have lived all year round in an ingested tank? Also why did they rapidly change colour once in the pond?

 

[Andy Sager]

With rosey barbs, the males get that deeper rosey color and the females generally remain the same color as the one in the top photo with just a hint of red when you look at them from the right angle.
As to why they turned color, they either reached maturity or they were in a better situation in the pond than they were in the tank. Could be either.
As for them being tropical, yes they are. But the pond water may not have gotten as cold or they were there long enough to have gotten used to the temp. Most barbs these days are not from wild stock so they are used to much different parameters than their wild counterparts. By all rights, half the fish in a centralized system that's half Tropical fish and half Goldfish should be dead as they both should be in different water. Yet they survive. Not sure if they were wild fish if that would still be true.

Hope this helps

 

[Samdaman]

It did help thank you so very much