Why are fish brightly colored?

[FPDocMatt]

Land creatures naturally evolve toward being brown. The brightly colored animals get picked off by predators.

So why is it that so many fish are brightly colored? What evolutionary advantage do bright colors convey?

 

[hogpark7430]

So divers have something to take photos of.

 

[DevonDiver]

I'm not a marine biologist, but here's my assumption;

1) Coral reefs are bright and colorful. Fish that live on coral reefs are 'camouflaged' into that environment.

2) Fish that don't predominantly live on coral reefs tend to be silver. Silver coloration helps 'disguise' the fish by reflecting light in the water.

3) Some fish and other marine creatures may be toxic if ingested, or possess toxic spines etc. Those creatures often evolve a 'warning' through bright coloration.

4) Many fish will have bright coloration for species identification, primarily for breeding purposes. Again, that's not necessarily detrimental given the surrounding colors of the reef

5) Because of light behaves differently underwater, and predators may not see within the same light spectrum as humans, it's feasible that the coloration evolved to effectively camouflage the fish to their natural predators - even though they may seem bright and obvious to us (humans).

6) Many fish have broken coloration - breaking up their outlines/body shapes. Some have 'false' features that may disorientate a predator. Examples of this are 'false eyes' on the tails etc.

 

[agilis]

Not all land animals evolve toward brown. Zebras, for example, were originally all brown/black, and are still born that way, illustrating the way evolutionary development is often mirrored in fetal development: the white stripes, it's now believed, may have evolved as a deterrent to infestation by African biting flys, a serious health problem. Light refraction from the striped pattern seems to repel these insects.

Many fishes are brightly colored, but at least as many are not. Countless different survival and mating strategies involving considerations of camoflage; indications of venemous capability or poisonous flesh, genuine or false flag; infinite possibilities serving different purposes. Sea creatures may also perceive things differently than we do, have different visual images. Light's properties in water play a significant role: bright red is erased from the spectrum in deeper water, the reason many deep water fishes are that color. Bright silver can vanish when you look upwards toward the surface. Patterns are often effective in misdirecting a predator's strike, other patterns advertise things like parasite cleaning services, earning that creature some degree of protection from predators, and also for creatures that just look like them. There are all sorts of signals involved in fish coloration and patterns, the meanings of which we can only guess at.

 

[divad]

So why is it that so many fish are brightly colored?

Because they're gay..................................................................................(I mean happy )

 

[nimoh]

In addition to the Zebra example, there are also a lot of snakes and birds that may or may not be camouflaged in their environment.

 

[FPDocMatt]

I'm not a marine biologist, but here's my assumption;

1) Coral reefs are bright and colorful. Fish that live on coral reefs are 'camouflaged' into that environment.

2) Fish that don't predominantly live on coral reefs tend to be silver. Silver coloration helps 'disguise' the fish by reflecting light in the water.

3) Some fish and other marine creatures may be toxic if ingested, or possess toxic spines etc. Those creatures often evolve a 'warning' through bright coloration.

4) Many fish will have bright coloration for species identification, primarily for breeding purposes. Again, that's not necessarily detrimental given the surrounding colors of the reef

5) Because of light behaves differently underwater, and predators may not see within the same light spectrum as humans, it's feasible that the coloration evolved to effectively camouflage the fish to their natural predators - even though they may seem bright and obvious to us (humans).

6) Many fish have broken coloration - breaking up their outlines/body shapes. Some have 'false' features that may disorientate a predator. Examples of this are 'false eyes' on the tails etc.

Gee, you sure sound like a marine biologist. Thanks!

 

[TSandM]

There was actually an article in one of the throwaway dive magazines a year or so ago on this topic, and the answer is that nobody knows.

Fish where I live tend to drab colors, which helps them blend in with their background, but there are spectacular exceptions, like the brilliant Vermilion rockfish. But they live in deep water, so for all I know, they may appear black to everyone around them. China rockfish, which are blue-black and bright yellow, are a bit harder to explain, because they stand out even without lights. Neither fish is poisonous, although all rockfish have venomous spines.

There has to be SOME advantage to the colors, but whether we can perceive it with our optical equipment or not is another question.

 

[DocVikingo]

There was actually an article in one of the throwaway dive magazines a year or so ago on this topic, and the answer is that nobody knows.

Mayhaps this -->
Why Are Reef Fish so Colorful?

Regards,

DocVikingo

 

[FPDocMatt]

Mayhaps this -->
Why Are Reef Fish so Colorful?

That was a pretty long article to spend 15 minutes reading, only to find out that the answer is, "Nobody knows".