Care & feeding guide

What to Feed Plecos & Bottom Feeders: Algae Wafers vs Sinking Wafers

Plecos, corys and loaches need food that sinks. Which wafer to pick, feeding at lights-out, how long to leave it, and pulling leftovers.

Plecos, bristlenose, corys and loaches eat on the bottom, and many of them feed at night. Food that floats never reaches them.

Give them a wafer that sinks and holds its shape, feed it around lights-out, and take out what's left.

A sinking wafer, fed in the evening, is how bottom fish get their share.

At a glance

Best staple A sinking wafer made for your fish
When Late in the day or after lights-out
How much What they finish in the bag's time
Leftovers Take out what's left; nothing overnight
Plecos also need Wood to rasp and some vegetable
Avoid Flakes only, or a pleco left to clean

Pick the right wafer

Algae wafers for plecos and bristlenose. Sinking wafers, with more protein and fat, for corys and loaches.

Two scenes on a sandy aquarium floor: a bristlenose pleco on a green algae wafer by driftwood, and three corydoras catfish around a brown sinking wafer — Plant-leaning grazers and omnivores get different wafers.

Algae wafers

Mostly vegetable. Hikari makes its Algae Wafers for plecos and other algae eaters. Fluval says its Algae Crisps suit all plecos and ancistrus (bristlenose).

Sinking wafers

More fish or insect protein. Hikari makes its Sinking Wafers for smaller bottom feeders such as corydoras and loaches.

The numbers show the difference. Hikari's algae wafer is 33% protein and 4% fat. Its sinking wafer for corys and loaches is 36% protein and 9% fat.

Compare 10 bottom-feeder wafers: protein, fat, fiber and moisture

Pick by the fish first: an algae wafer for a pleco or bristlenose, a sinking wafer for corys and loaches.

Food	Made for, per the maker	Protein	Fat	Fiber	Moisture
Hikari Algae Wafers	Plecos and other algae eaters	33.0% min	4.0% min	3.0% max	10.0% max
Hikari Mini Algae Wafers	Smaller plecos and algae eaters	33.0% min	4.0% min	3.0% max	10.0% max
Hikari Sinking Wafers	Corydoras, loaches and other small bottom feeders	36.0% min	9.0% min	4.0% max	10.0% max
Hikari Micro Wafers	Tropical fish, including catfish	44.0% min	8.0% min	2.0% max	10.0% max
Fluval Bug Bites Algae Crisps	All plecos and ancistrus	43.5% min	4% min	3% max	7.5% max
sera Viformo Pleco Tabs	Plecos	33.5% min	7.0% min	5.3% max	8.0% max
sera Pleco Chips	Plecos	29% min	9% min	6.8% max	not listed
Tetra PlecoWafers / Cory Wafers	Plecos / all bottom feeders	not listed	not listed	not listed	not listed
Aqueon Algae Rounds	not listed online	not listed	not listed	not listed	not listed
Zoo Med Pleco Banquet Block	Small to large catfish	1.0% (as published)	not listed	not listed	not listed

Figures are each maker's guaranteed analysis. Tetra and Aqueon don't publish theirs online, so read the package.

Zoo Med's block isn't a wafer. It's a slow-release block with wood fiber and 23.0-28.0% calcium: one block for 2-3 small catfish or 1 medium to large one, per Zoo Med.

Why it has to sink

Flakes float. Bottom feeders only get what drifts down, which is often nothing.

Two views of the same tank: flakes floating at the surface with corys searching an empty bottom, and corys eating a wafer resting on the sand — Food has to land where your bottom fish eat.

Flakes float at the top. A tank with corys, loaches or a pleco needs a food that sinks too.
Wafers sink fast and hold their shape. Hikari says its wafers keep their shape for a long time, so slow grazers can eat at their own pace.
Sinking food is harder to see. NorthFin says portion control matters more with sinking food. Check the bottom before you add more.

Feed at lights-out

Many bottom feeders are night feeders. Feed late in the day or after the lights go off.

Hikari says many bottom feeders are nocturnal, so feed late in the day or at night. NorthFin says feed plecos after lights off. sera says evening for night-active fish.

Lights off. Wait until the tank light goes off, or feed late in the day.
Wafer in. Drop in only what your fish will finish in the time on the bag.
Leftovers out. When that time is up, take out what's left with a net or gravel vacuum.

Lights off, wafer in, leftovers out.

How much, and for how long

Only what they clean up in the time on your bag. The label is the final word.

The makers give very different times, because the foods are made differently:

Hikari Algae Wafers: no more than your fish finish within 2 hours.
Hikari Sinking Wafers: what they eat in 20 minutes, then remove the rest.
Hikari Micro Wafers: about a minute's worth, 2-3 times a day.
Fluval Algae Crisps: two minutes' worth, two or three times a day.
sera Pleco Chips: sparingly, once a day, in the evening for night feeders.
Aqueon (general advice): what they eat in 2-3 minutes. Remove food still there after five minutes.

Two tank floors: one bristlenose pleco with a single algae wafer, and the same pleco beside a pile of five wafers — One fish needs a small amount, not a pile.

Bag gives no time? Use 2 hours. That's the longest any maker publishes. Then take out whatever is left.

Nothing stays overnight

Never leave a wafer in until the next day.

Don't stack them up

Check that yesterday's wafer is gone before you add a new one.

Feeding schedule

Feed once in the evening for most wafers, then follow your bag.

Fish	Wafer	When	How often	Take leftovers out after
Plecos and bristlenose	Algae wafer	After lights-out	Once a day (sera); Fluval says 2-3 times a day	Up to 2 hours (Hikari)
Corys and loaches	Sinking wafer	Late in the day	As your bag says	About 20 minutes (Hikari)

Plecos need more than wafers

A pleco is not a tank cleaner. Feed it a sinking algae wafer, plus wood to rasp and some vegetable.

An aquarium with a bristlenose pleco resting at the mouth of a cave, a piece of driftwood, and an algae wafer on the sand in front — Wood, a cave and an evening wafer. Tap a number to see why.

Driftwood: bristlenose rasp wood, and NorthFin says the fiber helps their digestion.
Cave or hide: plecos are night feeders and need a place to hide.
Algae wafer: a sinking green wafer is the backbone of a pleco's diet, per NorthFin.

Not a tank cleaner

NorthFin says plecos can't live on tank algae alone. No maker says they can.

More than algae

Hikari says plecos need plenty of vitamins and minerals, on top of algae and vegetable matter.

Wood

NorthFin says bristlenose rasp wood and the fiber helps digestion. Other makers don't mention wood.

Size

Common plecos and bristlenose grow to very different adult sizes. Check the care sheet before you buy.

Corys and loaches

A sinking wafer or tablet, not just flakes from above.

give a sinking wafer, tablet or pellet. Aqueon says catfish and loaches do best on these.
pick a wafer made for them. Hikari's Sinking Wafers carry more protein and fat (36%/9%) than its algae wafer (33%/4%).

Don't

count on flakes drifting down from the fish above.
leave sinking wafers in past the time on the bag.

Corys and loaches live on the bottom, and many do better in groups. Check the care sheet for your species.

Leftovers and cloudy water

A wafer that's turned to mush has been in too long. Take it out.

The same tank corner twice: cloudy water with a crumbling, mushy wafer on the sand, and clear water with a clean sandy bottom — Pull leftovers on time and the water stays clear.

Wafers are made to hold together. Hikari says they don't dissolve quickly. A wafer that clouds the water has been left too long.
Use a gravel vacuum to lift out crumbs from the bottom.
Test your water. Leftover wafer turns into ammonia.

Shrimp and snails in the tank

They'll pick at wafers. But no wafer maker says its wafer is shrimp-safe.

A red cherry shrimp and a nerite snail picking at the edge of a green algae wafer on a stone — Shrimp and snails will graze a wafer, but keep a shrimp food as their staple.

Hikari's Mini Algae Wafers and Aqueon's Algae Rounds name shrimp or crustaceans as eaters.
No wafer maker publishes a copper level or calls its wafer shrimp-safe. Hikari lists copper sulfate as a trace mineral, without an amount.
Keep a shrimp food as the staple for shrimp. Our snail care sheet says nerites in a very clean tank may need an algae wafer or blanched vegetable.

Storing wafers

Keep them cool and dry. Hikari says use the package within 90 days of opening.

Hikari says keep wafers cool, out of the sun, and away from moisture and heat.
Use an open package within 90 days, per Hikari. Other makers don't say.

Quick answers

What do I feed my pleco? A sinking algae wafer in the evening, plus wood to rasp and some vegetable. Hikari and NorthFin both say wafers alone aren't enough.

How many wafers? Only what your fish clean up in the time on the bag. Hikari says 20 minutes for sinking wafers and 2 hours for algae wafers. Take out what's left.

Will my pleco clean my tank? No. NorthFin says plecos can't live on tank algae alone. Feed it.

Do corys need a special wafer? Hikari makes a separate sinking wafer for corys and loaches, with more protein and fat (36%/9% vs 33%/4%).

Why are my wafers falling apart? They're made to hold their shape. A wafer that clouds the water has been left in too long.

Are wafers safe for shrimp? The makers don't say. No wafer maker publishes a copper level, so keep a shrimp food as their staple.

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Reviewed by our team 2026-11-09. Nutrition figures are each maker's published guaranteed analysis.