Will these snails starve without algae?

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A reader asks how he should feed snails?

I live in Mallorca, and due to the bright light we have here, I’ve been plagued by algae in my 126 l community tank. Having tried everything else, I recently added six Zebra snails. They are doing a fantastic job of eating the algae, to the extent I can see them running out of sustenance before long. If they do eat all the algae, how should I feed these snails? I don’t overfeed my fish so there’s unlikely to be any surplus fish food for them to find.

HENRY PARTRIDGE, VIA EMAIL

Neale says: Algae-eating snails, and indeed algae-eating shrimps and fish, will all do perfectly well on things like algae wafers and softened vegetables, such as blanched lettuce or cooked spinach. Most will consume bits of flake food too, though I’m certainly not advocating the old ‘let them eat leftovers’ approach to feeding. Even if you can’t see it, there’ll be algae such as diatoms growing on all solid surfaces, especially the glass walls of the tank, and the Nerites will be grazing on that pretty much all the time. Because algal cells are microscopic, the glass can seem clean but actually has a thin layer of cells that the snails will graze. In fact, the algal film is largely what Nerites eat in the wild.

Basically, unless your aquarium is spotlessly clean and utterly devoid of algae, it’s highly unlikely your Nerite snails will starve — assuming the tank isn’t wildly overstocked with them, that is. Hard to say what the right number would be, but something like 20 l per snail sounds about right to me.