Caffeine thought of the day... in which fish, is there the most / least difference, between males and female's???

[Magnum Man]

it's funny how some fish, even knowledgeable fish keepers, can't tell the difference in the sexes, then there are some fish, that look so different, they don't even look like the same species, endlers and guppies, a prime example, of the latter, and angel fish a prime example of the look a likes... from my experience.... anyone want to list some you can't tell apart, or some so different, they look different species, and or discuss the evolutionary advantage to either???

these are a few of my Santa Maria Endlers, a prime example of extreme differences between males and females

and my Angel fish, for example, I have no idea of their sex...

 

[Back in the fold]

Guppies for sure as the one fish easiest to tell the sexes . Even someone who doesn’t know tropical fish can tell the difference . The hardest to differentiate is , to me , Angelfish . I’ve never been able to tell even when I thought I knew .

 

[Colin_T]

Glossolepis incisus rainbowfish from New Guinea. Male is red, females have no red.

 

[anewbie]

Many species of apistogramma seen side by side you would not realize they were the same species for example nijjensi; can't locate my pictures right now but just google apistogramma nijjensi

 

[emeraldking]

There are so many fish species where males differ a lot from the females. I could go on and on with listing fish species with phenotypical differences between both sexes. But I'm curious for all the replies overhere...

 

[gwand]

Melanochromis johannii: Males are deep blue to purple with light blue to black horizontal stripes. Females are orange or yellow.

Pseudotropheus saulosi: Males are blue with black bars. Females are yellow.

Labidochromis caeruleus Males and females look alike. You have to examine their vent to be certain of sex.

 

[Colin_T]

Peacock cichlids (Aulonocara species). Males are blue or primarily blue with red, yellow or black markings, females are silver grey.

 

[Rusty_Shackleford]

Sure you could say any Malawi cichlid because of the color difference between a male and female.
But for size difference consider Lamprologus callipterus from Lake Tanganyika. Adult females are shell dwellers and top out at 1.8"-2.0". While males are too large to fit in shells and hunt in packs, they grow to about 5.0". Extrapolate that out a few times and it's like having a 20" male and an 8" female. Quite the size gap.

 

[Innesfan]

The hardest to differentiate is , to me , Angelfish . I’ve never been able to tell even when I thought I knew .

Yes, that intrigues me more than those that manifest sexual dimorphism--the ones who try to keep it a secret from us, especially the evolutionarily advanced species such as Angelfish and Discus.

 

[anewbie]

Yea I have a breeding pair of chocolate cichild but no clue who is he and who is she