These are generally caught during the lead up to, and through the rainy season in most dams, rivers and lakes throughout the country.
This is purely because they are easier to find, as they are stuck on the anthills looking after their nests, and so any food that comes to them will get "gobbled up", and the main thing that they eat during this time is the flying ant, and occasionally algae when it drifts there.
As said earlier they also eat the small camel worms if used instead of flying ants or "grubs". They have been known to eat "Christmas or Rose" beetles also, as they become very opportunists feeders at this time.
Once they are "on" it is important to use as fresh ants as possible, they seem to know when the ants are "sour" and will not feed on them at all.
Either float you ant over the top of the anthill/breeding bank, or slowly pull it along the bottom with as little weight as possible.
The bites on the bottom are very delicate most of the time, and if you think that you are stuck, then just hold the rod and watch the tip, and see if the bottom "pulls back".
If it does - STRIKE !!

SECRET TIP
Have you ever noticed that the Chicamba weed and sticks that you bring back, in shallowish water (2 to 6 feet), seem to have been invaded by borers ??
Well those holes are made by the larvae of the Caddis fly, and Mellies LOVE them. Simply take the stick or weed out, and look for the holes, and you will see that many have like a silken cocoon in them, and often there appear to be three hairs or feelers sticking out. Well that is the back end of the larvae. Just niggle it with the end of a porcupine quill and it will come out the other end of the hole. In Chicamba weed you can simply break they weed open, and chase them out of their cocoon. Keep them in water with a small piece of wood on for them to settle on to, as this makes it easier to catch them in your bucket. Keep them out of the sun and if possible cover them completely. You will need quite a few for a days fishing, and generally try to only keep the larger ones.
Fish these either on a float just off the bottom near the structure or pull them gently along the bottom.

This is usually from about the middle of October through to January/February but it depends on the rainy season and the dam levels to a small extent.
These fish do not just breed on anthills, as generally there are not enough anthills for all the Mellies in the lake or dam and so they often create "breeding banks" along the shore on the cleaner bottoms.

They move around during the rest of the year and seem to feed primarily on algae and other green vegetation, so in most local dams they can be caught algae or slime along the weed edges and around the rocks where the algae grows.

In Kariba you will see the "Pros" using spinners with a single hook, with two or three worms on the back, and spinning through the trees (30 to 70 feet deep YES THAT DEEP), or "jigging and shaking" them on the bottom in Eel Grass beds around humps and ridges.
This generally produces larger fish but takes a bit of practise to know the bites from the trees and weeds.

You can of course still catch them using the traditional ledger (sinker and hook style) but you must try and find an Eel Grass bed or somewhere they will be resident and feeding.

Generally shallower areas (6 to 15 foot) prove to be the best for this method of fishing, and if there is some vegetation it also helps. Look on the Chicamba and other weed, for signs that they have been feeding on the leaves or watch for floating eel grass pieces and try to establish where it is coming from, as that is where they are feeding.

When the water is rising they will move to the shallows and into the grass, and the most suitable method is to use a bubble float with a hook some 18 inches to 2 foot behind it, and cast it into the shallows and slowly retrieve it such that it leaves a wake on the surface.
This wake seems to trigger their attention, and their curiosity seems to get the better of them and they just have to grab it, and see what it is.
The fish at this time of the year are not always big, but they are a very edible size, and the scrap trying to get it our of the grass is good fun.
If they are nesting, the red on the underbelly will very prominent, sometimes even very dark purple, and they are very aggressive towards anything that gets close to their nests.
HOWEVER, be warned they appear to be very clever and if you drop two or three they will go right off the bite. Also when fighting them, try to get them off the nesting area and then play them, as they do not seem to disturb the others that way.

SECRET TIP
If you see the Mellies jumping and battling to eat at the edges, because the weed is too far out of the water, and they do not want your algae/slime offerings, creep over there very quietly and break some of the reeds/weed down so that it hangs into the water. This will cause them to gather there, and they get quite excited about it and you can generally catch a few. You may have to leave them for a while and then return a bit later if they scare when you bend down the reeds.
(This is known as the "Darters Whistle")