well it really depends on what fish your talking about, usually males will be more colourful and appear more dominate. certain fish such as electric yellows have a black colour around there mouth like a "beard" and they tend to have alot darker fins. frontosa males will grow a hump on its head this is the same with blue dolphins. but yea theres alot of types of African cichlids so which are you really refering to?
I want male lion head fish how can I sex them
if it has a slit
you can't
The vets can normally tell by looking underneath their wings
There is no one specific way to tell the difference between male and female fish. Different species have different ques, and in the vast majority of fish, there is really no reliable external way to tell a fish's sex.
At the current time they appear not to have been bred in captivity. No obvious differences are visible between male and female Black African Knife fish (Xenomystus nigri).
You can tell the sex of fish by the size and shape of their fins and tails. If in doubt, just ask them.
Look at the fish's bottom side. If the "anal fin" is fan shaped the fish is a female, if the fin is thin and pointed like a nozzle then the fish is a male. In the male this fin is called a 'gonopodium'
One way to sex a tropical fish is to observe a mature male or female. The female will eventually lay eggs and the male will show his penis if a mature female is around.The way to sex a tropical oscar fish is to simply observe whether or not the female lays eggs. It is not possible to tell by just looking at the fish.
My understanding of the term "Anamorphic" in relation to gender would imply that the fish is progressively changing sex. If this is what you mean then there are a couple of species that come to mind like the Barramundi and the Marine Clown fish. There are also several African cichlids that do this too. What happens is at a certain stage in the life of the fish it changes sex.
Goldfish are pretty hard to sex unless you're very good at it such as a breeder, but in shubunkins, typically the female will be plumper than the male
In bluegills,it is really hard to tell the difference unless the fish are spawning.Males guard the nest from small fish that would eat the eggs,and it is then one can tell the males from the females.The male is larger,and of a darker color,with a coppery colored band across the head. Females are paler,with faded bands on the flanks.