Algae Wafers: Who Eats Them and How Much to Feed

An algae wafer is a flat, sinking food disc made mostly of plant matter like spirulina and kelp. It drops straight to the bottom, so fish that never come up for flakes get a meal. They're useful, but they're also one of the easiest ways to overfeed a tank.

Who eats them

• Plecos, especially bristlenose plecos. They'll rasp a wafer down to nothing overnight.
• Snails, including nerites once the glass algae runs low.
• Shrimp. Amano and cherry shrimp swarm a wafer.
• Crayfish and crabs. See can crayfish live with fish.
• Corydoras and loaches, though they need meatier foods too.
• Otocinclus sometimes, though many prefer grazing soft algae and biofilm.

Who shouldn't live on them

• Corydoras and loaches are omnivores. Wafers are a side dish; give them sinking pellets, frozen bloodworms or brine shrimp too.
• Fish that need meat, like most catfish other than plecos. Look for "carnivore" or "meat" wafers instead.
• Plecos that eat wood. Many plecos also need driftwood to rasp on.

How much to feed

A good rule: feed what's gone in a few hours, or by morning for a nighttime feeder.

• One adult bristlenose pleco: roughly one wafer a day, or every other day in a tank with plenty of algae and driftwood. Tank algae alone isn't enough to keep one healthy.
• A small group of shrimp or snails: a piece of wafer, a few times a week.
• A mixed tank: break wafers into pieces and spread them out so the shy eaters get some.

If there's wafer left the next day, cut back.

When to feed

Plecos and many loaches are most active at night. Drop the wafer in right after the lights go off, so the fast daytime fish don't steal it.

Signs you're overfeeding

• Mushy wafer bits left the next day.
• Cloudy water or a white fuzz (fungus) on leftovers.
• A sudden snail explosion.
• Rising ammonia or nitrate on your test kit. See reading your test kit.

Remove leftovers with a turkey baster or a gravel vacuum.

Mix it up

Wafers shouldn't be the only food. Plecos and snails also like blanched zucchini, cucumber or spinach. Weigh a slice down with a plant weight or a fork, and take it out within a day.

Sources (2)

AquariumStoreDepot: Bristlenose Pleco Care Guide · TankLore: Do I Need to Feed My Bristlenose Pleco?

Related: Ten Fish That Thrive Best In A River Tank Style Aquarium (Riparium) · Native North American Fish for Aquariums (and the Rules on Collecting)