Mexican_tetra/ blind cave fish

[fish48]

The blind cave fish is one of those fish you either like them or you don't, when I bought a group of them about 3 years ago the shop assistant laughed and said why do you want those horrible looking things I gave him a simple answer I like them and find them fascinating and i want to breed them, I kept a group of 7 in a 3-ft tank I recently decided to see if I could get them to breed before they get too old,
blind cave fish at 5 weeks old

 

[StripySnailGirl04]

The blind cave fish is one of those fish you either like them or you don't, when I bought a group of them about 3 years ago the shop assistant laughed and said why do you want those horrible looking things I gave him a simple answer I like them and find them fascinating and i want to breed them, I kept a group of 7 in a 3-ft tank I recently decided to see if I could get them to breed before they get too old,
blind cave fish at 5 weeks old
View attachment 153125

Perhaps not dazzling with colours but certainly fascinating. Good luck with the fish breeding!

 

[Oblio]

If blind cave fish are bred in an environment with light, will they eventually evolve to have sight?

 

[GaryE]

If blind cave fish are bred in an environment with light, will they eventually evolve to have sight?

Evolution is random, so while it could happen, there's no reason why.

I was in Belize floating in an inner tube when a huge shoal of their sighted relatives found me. I was exfoliated, like a spa, within seconds. They were all over me, high speed grazing. It was cool. I think. Maybe.

 

[Oblio]

Evolution is random, so while it could happen, there's no reason why

If there were a random mutation that allowed, for instance, a fish to see changes in light (rather than full sight), and that allowed the fish to better locate a mate, then that gene mutation would be propagated.

I was exfoliated, like a spa, within seconds. They were all over me, high speed grazing. It was cool. I think. Maybe.

 

[fish48]

If blind cave fish are bred in an environment with light, will they eventually evolve to have sight?

it would be almost impossible to evolve to have sight they are born with eyes as you can see in the photo very soon the eyes will cover over

 

[Oblio]

it would be almost impossible to evolve to have sight they are born with eyes as you can see in the photo very soon the eyes will cover over

That's interesting. I'm curious to understand what natural selection advantage was conferred by the eyes being covered over. I realize that cave fish do not need to see, at least in the normal spectrum of 'visible' electromagnetic radiation, but I was under the impression that evolutionally changes were selected based on the ability of the species to survive, thrive, and reproduce (passing on those genetic mutations).

 

[Oblio]

Progeny Of Blind Cavefish Can 'Regain' Their Sight

Hybridizing blind cave fish from different cave populations can partially restore the vision of their offspring, biologists have found. The study suggests that genetic engineering can override, at least in part, half a million years of evolutionary change in one generation.

www.sciencedaily.com

 

[Byron]

The eyeless, troglomorphic form is found only in Mexico but this species, Astyanax mexicanus, is in fact widely-distributed from the southern United States (Texas and New Mexico) through Mexico itself and into Guatemala. The surface-dwelling form is something of a generalist and can be found in all kinds of habitat from flowing streams and rivers to ponds and lakes. The blind form occurs only in underground caves and caverns. The two forms may have diverged as recently as within the last 10,000 years, with the blind form losing its eyes and much of its pigment. This probably happened because the fish needed better development in other sensory areas. Losing unnecessary and energy-consuming aspects of its physiology allowed it to devote more energy to developments such as increased numbers of taste receptors on the head. Recently, tests have been conducted regarding the impact of eye lens transplants from the surface form to the blind form. Although the fish did not regain sight, they did grow eyes complete with pupil, cornea and iris.

[from Seriously Fish, posted solely for additional information to the thread, I make no comment.]

 

[emeraldking]

I like them and find them fascinating

I'm keeping them as well. And I find them fascinating as well. I think it's even weird that the employee made that remark. For a serious employee would not even start a remark like that. An lfs employee should consider that the customer might like a certain breed. Not everyone will go for the most bright colored fish.
I keep mine in an open (top is open) paludarium.