Why purple and yellow?

[damsels are not mean]

Two iconic aquarium fishes which look very similar with their unique and odd color pattern of purple and yellow: The royal gramma and royal dottyback. Despite their similarities, these fishes are not really closely related and come from different parts of the world. Does anyone know (or have any research anywhere) what the advantage of this color pattern is? I'm just curious. Seems unlikely purple and yellow evolved randomly on multiple fish.

 

[Spare time]

Convergent evolution is not that uncommon. I don't know the reason for it in this, but it could also be for no selective pressure related reason. My guess is that it relates to communication, as color often does. I'll post a link to some info when I find it.

 

[Spare time]

"The reversal in brightness ofbody areas inGramma loreto(Poey) (Fig. 6) could be used as a broadcastsignal, depending on the contrast with the background" from The UV visual world of fishes: a review
Losey et al 1999

 

[G Santana]

Because they thought it was a fantastic combo lol

 

[vetteguy53081]

Basslet more feisty and brilliant in color

 

[ying yang]

Why Are Reef Fish Colorful

Have you ever wondered why reef fish are so colorful? As it turns out, this question is more complex than one might think. Here are a few theories that might explain the phenomenon.

dipndive.com

According to this article and another I just read,there's alot if unknowns why fish on the reef so colourful and why and what do the fishes see and the purpose,just alot of guesses it seems.
Article not just about yellow and purple but all the colours.
My guess would be that reef fish so colourful to blend in to surrounding ,also to attract mates,hierarchy,signalling,and blending in imo would be a strong reason,like purple coraline algae,gsp mats,and alot of corals are purple,like 4 of my 7 zoa's body's are purple so maybe alot of stuff on the reef is purple or some shade of blue/ purple so therefore alot of fish are purple but just a guess,I know alot of lake and river fish have whiter underneaths so blend in if anything beneath them looking up and same for colour on top of them so if above it and looking down they blend in like grey/ blue if clear water and brown if bottom dwellers living on sandbeds/ mud beds etc so evolved to their surroundings to be able to hide from predators or if a predator themselves can sneak up on prey easier.

I myself probably like many on r2r have watched numerous documentaries on fish whether in reefs or rivers/ lakes or in deep blue sea and often gets mentioned about river/ lake fish trying to go dull over evolution but reef fish seem to gone completely different direction and got as colourful as can be but off course can't remember why they said they do this ha ha but thought I'd leave a comment in this thread to see what others say and give my opinion ^_^

 

[JGT]

Mother Nature just thought that the color combo was super cool so do it twice.

 

[i cant think]

I’m pretty sure reef fish get brighter to blend in with the corals around them whereas fresh water/river fish get fuller to hide in with foliage that falls into the water. I think this is a similar reason why many reef fish found in extremely shallow water on sea grass mats are elongated and sometimes dull.

 

[Spare time]

I think it is always important to realize that, through the fish's eyes, they look completely different. Vibrant coloration is almost always related to communication or sexual selection.