Fish patterning, coloration, what can we tell by looking at them???

[Magnum Man]

My caffeine thoughts this morning, as I lounge, and get woke up… started with my seeing a pretty small Zebra Oto, that’s in my mixed Cichlid tank… wondering why they don’t eat it… the largest of the Electric Blue Acarras, could easily make a meal of it… I’m actually surprised that all 4 Zebras are thriving in this tank… made me wonder if there was something to the black and white striped pattern, that says don’t eat me, for some reason ( like the pattern on a sea snake ) or??? Many fish have the same pattern I have a variety of loaches, that carry the same pattern, some plecos… just with fish I currently have, I can think of several I don’t have as well…

Then on some small tetras, @GaryE, and I’ve talked before about the camouflage that silver provides smaller fish, but interesting that my Tin Foil barbs, carry the same silver color, but in giving this one some thought, they start out small, with no color on their fins, and as they grow, develop very red fins, thinking that they may color up, after they have grown large enough, that they no longer have to camouflage..

The other day, the Amazon Leaf fish was the topic of one thread…. Much different camouflage technique there…

Then, there are the brightly colored fish… I’m assuming most of these are starting out plainly, as protection, and develop the color to attract mates…

To circle around, back to the striping, even most angels have the striped pattern, though I can see that as a camouflage technique… but on the Zebra Oto’s, and some of the similarly striped loaches, and plecos, the pattern would be less effective, makes me wonder why that pattern was copied over with so many species???

 

[CassCats]

Stripes often blend with sand, wood, and gravel with the light dappling from the sun on the underwater surfaces looking a lot like their stripes.

Not to mention many striped fish are also either cryptic fish (plecos) or schooling fish where the bold markings are then used to confuse predators (think like zebras for example, this would be also utilized by otocinclus who shoal).

The bright fish like cardinals and neons and such, they often come from very dimly lit areas or very silty waters where visibility is an issue, so to stay together in numbers, they have bright reflective strips that are visual cues for the group to stay within sight of one another for safety in numbers.

 

[Magnum Man]

Just the size and shape of the Oto’s would lend to them easily being dinner, and they are often swimming in the open, or grazing on extended roots of terrestrial plants, making them easy targets???

 

[CassCats]

Just the size and shape of the Oto’s would lend to them easily being dinner, and they are often swimming in the open, or grazing on extended roots of terrestrial plants, making them easy targets???

You'd think so, but no.

They have spines, like many catfish do, and armored plating, like plecos. They blend in very well with the wood and rocks around them. They'll often be in open areas that get a lot of sunlight that get a lot of algae, plus they're also nocturnal. So they'll sleep hidden during the day in nooks and crannies but come out to forage at night when most of their would-be predators don't tend to see well enough to catch them. Most predators that they'd have to really worry about are usually birds such as herons, who would view the fish from above, but hidden among the rocks, the stripes and mottling on otocinclus hide them in plain sight.

Putting them in a planted tank, yes, they stand out, because their natural environments tend to have very little plants. Usually found in streams and other areas that have plenty of rock or wood and botanicals that grow plenty of algae and biofilm for them.

 

[WhistlingBadger]

I wonder how fish see differently than us. Perhaps what stands out to us is invisible to them. But even to my eye, a tiger or leopard is strikingly bright, until you put it in its natural environment, remembering that most pray animals can't see orange or yellow:

Fish seem able to see more colors than ungulates, but I wonder if the same ideas are at play. It could be that maybe your zebra Ottos naturally exist in a more grassy or brushy environment where those stripes just disappear. I could definitely see that being the case with clown loaches and other "bright" fish. Rainbow and brook trout look beautiful out of the water in the sunshine. Down in the rocks, they are remarkably hard to spot.

Even I hunt in plaid shirts a lot of the time. In town they look pretty. Put them out in the woods and brush? They vanish.

 

[GaryE]

I think much has to do with our different eye structures.We can't even see ultra violet. Plus colour spectrums change with depth filtering light. Red is the new black.

I notice horizontal stripes tend to go with fast fish, lateral stripes with reed and plant stem species.

I know Otocinclus affinis has been reported in huge numbers in floating meadows - large tangles of floating plants and plant debris that operate like uprooted islands and are the homes of a lot of small fish. Mottling would work there. It would be good over gravel too. Sometimes when the surface is agitated and I use a strong led bulb, I get a dappled effect on the bottom, like sun in a stream. That would work.

Some fish want to be seen.

There's a cost to being good looking - guppy females have been documented leading colourful males before the noses of predators, because they are so %^%s annoying, I guess. Brightly coloured males get picked off, but maybe not before a female has chosen them as a partner. Since they aren't involved in raising the young, they are expendable then.

A friend found a killie species over leaf litter in the Central African Republic. He saw a shaft of light coming through the canopy onto a shallow stream, and the stream was golden with male killies showing off. The females were sensibly in the leaf litter, and were picking the males they liked the look of. So, I imagine, were predators like birds, insects and human fish collectors.

Those males were without camouflage. But they were apparently pretty hot - almost hot pink in effect.

Since it's all about only living long enough to breed, there's camouflage, but also good looks, the 'peacock tail' side of sexual selection.