It isn't unusual for a young fish to change colour as it grows older. I don't know about algae eaters specifically changing colours, but with goldfish and koi it's a pretty normal occurance, and with many african cichlids this will occur as well.

Usually young and newborn animals are differently colored then adult stage. It's natures way of camoflage for protection of preditors. Fawn's have spots, then loose them as they age. Ducks are usually a solid color to blend in with the parents underbelly etc.

Careful with the golden algae eater! It get's nasty as it ages and should only be kept with other semi-aggressive fish. They also don't eat as much algae after the first year. When they can fit a smaller fish into there mouths they usually do.

If this fish is for algae clean-up, a fleet of Oto cats or "true" Siamese Algae Eaters (SAE)are best.

Yes! I got so mad at the CAE that was in a community tank because I thought it contributed to the death of one of my gouramis because it kept harrassing it that I dumped it into my cichlid tank. Mean thoughts, but figured it would get eaten up!

Of course it's too fast, so it's survived and is still in that tank 4 years later, but it hides in the rocks most of the time.

I agree about the CAEs and believe that for tanks over 20 gal., dwarf plecos are a far better choice. I keep Octos in my 5 & 10 gal. baby tanks, but of all the algae eaters that won't harm very small fish, including the tiniest fry, it's hard to beat ramshorn snails.

I maintain a tankfull of brilliant reds and drop a single adult into each small tank. That way, I don't get overloaded with snails, the bright red color is kind of pretty, and the algae is kept in check.