The first time I bred multies I did almost nothing, and that turned out to be the correct amount of effort. One evening I was staring into the shellie tank, as you do, and noticed the sand near a shell was shimmering. It was not sand. It was a dozen fry the length of an eyelash, hanging just above the grains, dropping back into the shell every time an adult swept past. Shell-dwelling cichlids raise their own young better than I can, and the main skill in rearing them is knowing when to keep your hands out of the tank.
This is about Neolamprologus multifasciatus, the smallest cichlid in the world and the heart of what I keep. If you are still trying to get yours to spawn in the first place, that is a separate problem and I have written it up in why won’t my shell-dwellers breed. This piece picks up at the moment the fry appear.
Why hard water is doing you a favour here
Multies come from Lake Tanganyika, which is hard, alkaline and stable. The published range is roughly 8 to 25 °dGH and a pH somewhere in the 7.5 to 9.0 band, with most breeders settling around pH 8 and the mid-20s in temperature. My tap runs about 22 to 23 °dGH out of the cold line, calcium-heavy, and I buffer it up to hold a steady alkaline pH. That is a nuisance for anyone trying to keep soft-water tetras, and it is close to ideal for a shellie colony raising fry.
The point worth making is that for breeding shell-dwellers, hard water is not something to correct. Leave it alone. The one habit worth keeping is a buffered Rift Lake mix so the pH does not sag over a week between water changes, because a drifting pH stresses a colony more than a high one ever will. I keep a buffer routine ticking along and check the remineralise calculator when I am making up replacement water, but if your tap is already hard and alkaline you are most of the way there. If you are on soft water and want to breed these fish, that is where the real work is, and the RO mix calculator plus a good Rift Lake salt is the honest route rather than chasing it with additives.
What happens inside the shell
You will almost never see the spawn itself. The female buries a shell so only the mouth shows, sits in the entrance and displays until a male takes an interest. She lays the eggs deep inside the shell, backs out while he releases milt over the opening, and the water current draws it in. After that the male is surplus to requirements; she guards the shell mouth and he gets driven off her patch.
The eggs hatch in about a day. For the next week the fry are tucked down in the spiral of the shell living off their yolk sac, and the female fans fresh water over them with her fins and chases off anything that comes close. At roughly six or seven days they become free-swimming and start appearing at the shell mouth. That is the shimmer I described. They do not stray far at first; a shadow passes over the tank and they vanish back inside like someone pulled a string.
Brood size is small and the literature is vague on exact numbers, which matches what I see. A handful to a couple of dozen is normal, not the hundreds a livebearer throws. That is fine. Multies play a long game: the colony builds up slowly, batch on batch, rather than all at once.
The book behind Lagonia
The Hard Water Aquarium
My practical guide to working with hard, alkaline tap water instead of fighting it: reading your water, choosing and setting up the tank, and keeping and breeding the fish that thrive in it, from livebearers to Rift Lake cichlids and shell-dwellers.
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Leave them in, nearly always
Here is the part people get wrong because they are used to other fish. With most cichlids you think about separating fry to save them. With multies in a single-species colony, the default is to do nothing. The parents do not usually eat their own fry, the colony tolerates the young, and successive broods simply accumulate on the sand bed. A multi colony is a living thing that grows by itself, and pulling fry out breaks the very structure that makes these fish worth keeping.
I only intervene in two situations. The first is when the colony is already dense and I want the numbers for other tanks or to pass on, in which case I will lift a batch. The second is when there are tankmates in the tank. Adult multies will not bother the babies much, but almost anything else will treat them as food, and some Tanganyikans, savoryi being the classic example, will clear a shellie brood in a night. If you have mixed species, read what can actually live with multies before you blame the parents, because the honest answer is that most tankmates are wrong for a breeding shellie tank. A colony on its own is the most productive setup there is.
So the short version: single-species colony, leave the fry where they are and let the group build. Only reach for a net if you have a reason.
If you do want to pull a batch
When I lift fry I wait until they are properly free-swimming and venturing a centimetre or two from the shell, never while they are still half in the spiral. Catching them is a comedy. They are fast, they stay glued to cover, and a straight-sided net is useless against a fish that dives into sand. What works for me is coaxing the occupied shell gently to the front with the fry out, then cupping shell and babies together into a jug rather than chasing individuals around the tank.
A bare-bottom rearing tank makes life simple: easy to spot leftover food, easy to keep clean, a sponge filter running off the main system so the water chemistry matches. Match the hard, alkaline parameters exactly. The biggest killer of pulled fry is not predation, it is a mismatch in water or a slug of ammonia in a tank that was not properly cycled, so get the box filter mature first. If you are unsure your rearing tank will hold up, the stocking calculator and a basic grasp of the nitrogen cycle matter more here than any feeding trick.
Feeding the babies
Multi fry are cichlids, not livebearers, so they come out small and need small food. Newly free-swimming fry take baby brine shrimp or microworm straight away, and that is what I start them on. Freshly hatched brine shrimp nauplii are the thing they respond to best; the fry visibly fill up orange through the belly within minutes, which is a satisfying way to know they are feeding. I keep a hatchery going when there are fry about, and if you have not set one up it is genuinely easy, I go through it in hatching baby brine shrimp.
You do not have to hatch brine shrimp forever. After the first week or two I start crushing the colony’s normal dry food to dust between my fingers and dropping it in alongside, and the fry take it readily. A good quality fine powder or crumble made for fry works just as well. The rule I follow is little and often: two or three tiny feeds a day beat one big one, because small fry have small stomachs and uneaten food fouls a tank fast. In a colony tank where you are leaving fry with the adults, you may find you barely change your feeding at all; the babies pick at what drifts past and graze the biofilm, and they grow a little slower but with no effort from you.
Water changes matter more than anything fancy while they are growing. Small, frequent changes with matched hard water keep nitrate down and growth steady. Keep an eye on the glass for the usual green water or algae that a feeding-heavy fry tank can bring on, and ease off the food if it starts to bloom rather than reaching for a chemical fix.
When the mother turns on them
There is a moment that alarms new keepers. Around a fortnight after the fry go free-swimming, the female starts shooing her own babies away from the shell. This is normal. She is clearing the nursery for the next brood, and the half-grown fry are expected to move out to the edges of the colony and fend for themselves. In a healthy colony tank there is room for them to do exactly that, drifting to a quieter corner, claiming a spare shell of their own in time. Provide plenty of shells, more shells than fish, so the youngsters have somewhere to go when they are evicted. If you have crammed the tank with adults and left no spare real estate, that eviction turns into relentless harassment, so the fix is more shells and, if needed, thinning the colony rather than anything you do to the water.
The honest picture
Raising shell-dweller fry is less a technique than a frame of mind. Give them hard, stable, alkaline water, which if you are on hard tap you already have; give them more shells than fish; keep the tank calm and ideally single-species; and feed the babies small and often if you want them to shift quickly, or barely at all if you are happy to let the colony tick over on its own. The fish do the rest. I have raised far more multies by leaving the tank alone than I ever did by fussing with nets and separate tanks.
A note of sensible caution: these are guide figures from my own tanks and from the aquarium literature, not laws. Brood sizes, timings and temperaments vary between colonies and between individual fish, and test kits vary too. Watch your own fish, change one thing at a time, and let the colony tell you what it needs. If you want the wider picture of running an established group day to day, keeping shell-dwelling cichlids covers the long game.