How Much Should I Feed My Fish? A Beginner’s Guide

How Often Should I Feed My Fish?

Well, it's like humans. If you look at human adults, maybe we eat three times a day.
Versus a newborn baby that’s constantly crying for food—you might feed them eight times or more per day.

It could be perplexing that all the different fish food packages were saying something different. They would say feed them anywhere from one to three times a day…
What they can finish in two to five minutes… Like—that seems like a really wide range!

In the same way, we go by a general rule:

• Adults—feed about one time a day

• Juveniles in a grow-out tank—feed twice a day (morning and evening).

• Babies or newborn fry—feed three to five times a day or more if you're around.

That’s because they have really tiny stomachs, so basically you want to feed them tiny meals multiple times throughout the day so they’re never hungry.

What Is the Best Time to Feed Aquarium Fish?

Most fish are awake during the daytime—they’re diurnal. I would wait at least 10 to 15 minutes after the aquarium lights come on for the day, just so that all the fish are awake and alert and more likely to attack the food immediately—instead of letting it float to the bottom.

Nocturnal species like loaches or plecos wait until the aquarium lights are off for the day. That way the diurnal fish are less active, and the night owls have a better chance of getting food.

How Much Food Should I Feed My Fish?

And now, the hardest question… How much food to feed?

Unfortunately, it really depends.

• What’s the size of the fish?

• How active are they?

• Are they fast swimmers or ambush predators?

• Are they breeding or fighting all the time?

• What’s the water temperature? (Higher temps = higher metabolism = more food)

Some articles suggest feeding 0.5% to 2% of a fish's body weight per day.
Roughly 1% is a common recommendation. But I mostly keep nano fish—so that’s super difficult to weigh.

But you can try this trick instead…

A fish’s eyeball is roughly the size of its stomach. So, feed them the amount of food that fits in their eye.

Let’s say I have a school of tetras, and each eyeball holds about three nano pellets.
If I have 25 tetras, that’s 75 pellets. Let’s say that amount is roughly the size of a dime—I’ll use that size to estimate how much frozen food, Repashy, or other food to give. It’s all approximation. Make sure the fish have a slightly rounded abdomen.

Signs of Overfeeding

Every time you feed my fish, I observe their waistline. Here’s what I look for:

Overfeeding Symptoms:

• Swollen belly

• Excess poop

• Piles of uneaten food

• Cloudy water (bacterial bloom)

• Ammonia/nitrite/nitrate spikes

• Snail/worm population boom

Even though a fat fish may look cute, overfeeding can lead to serious problems like

• Fatty liver disease

• Constipation

• Bacterial/fungal infections from bad water quality

How to Fix Overfeeding

• Feed less

• Fast your fish one or two times a week.

• Remove uneaten food.

Removal timing depends on food type:

• Flake food—remove after 10 minutes

• Blanched veggies/Repashy gel food—can stay in the tank up to 24 hours

Also—make sure roommates or family members aren’t secretly feeding your fish.
Fish will always beg for food. They’re opportunistic feeders in the wild and don’t know when the next meal is coming. Even if you fed them an hour ago, they’ll still act hungry.

Bottom line: Hide all your fish food from your friends.

Signs of Underfeeding

Now if your fish have:

• Really skinny bodies

• Sunken abdomens

• Pale colors

• Dying off slowly

It might be time to increase their portion size.

But just be aware—these symptoms can also mimic internal parasites or worms.

For example:
I had a case where I was feeding my endlers, livebearers, plenty of food, but they were still fading away. I had to treat them with Paracleanse and Expel-P to make sure they were parasite-free. Thereafter, they were fine.

What If I Forget to Feed My Fish?

How long can fish go without food? Good news—adult fish can go over a week without eating. If you’re going on vacation, you usually don’t need a pet sitter.

Exception: Baby fish. They need to eat constantly.

In that case:

• Get a pet sitter, or

• Use an automatic fish feeder with a small opening and set it to feed multiple times a day.

Don’t forget to enjoy nature daily.  Thanks for reading!