I have a tank that has two sunfish in it. The older one that I've had for a few years won't eat anything but frozen bloodworms and insects. I've tried being more stubborn than him a few times with no avail, I'm almost certain he'd starve himself before he goes on flakes "cold-turkey". The younger one that I've had for almost a year will eat anything including flakes.

I don't really have a problem feeding the older one bloodworms, but it would be kind of convenient if I could feed them all flakes and/or pellets. Is there a way I can transition the older fish into eating flakes or pellets?


2 Answers 2


I am not a fish expert, but with a mammal we would feed the old and the new foods together, placing them in the same food bowl. This is done starting with a small amount of the new food, as the transition continues we give less of the old food and more of the new food.

I can see how this might be a problem with fish though, I have it on good authority that the flakes float on top and the blood worms tend to float to the bottom.

You will need something to keep the flakes and worms from separating in the tank, my authoritative source mentioned there is a "kinds of pastes used to make bait for catfish" that you may be able to use to combine the flakes and the worms.

What ever method you use you will need to include some of the new food with the old food, and make a slow and steady progression to using just the new food. Rapid diet changes are generally discouraged, as it can lead to digestive and health issues.


When introducing new food I've not fed to my fish before I do not feed them for a day (maybe even two days) before I give them the new food. I have a planted tank and I know that if they're really hungry, they'll start nibbling the plants so there is no real risk in skipping feeding for a few days (I actually find skipping a day every fortnight better replicates the natural environment they'd live in anyway).

When I introduce the new food, the fish will generally eat it immediately but if they don't (or if they start spitting it out and sucking it back in again) I know that they are just not hungry enough to eat it (assuming the food is appropriate for the fish, which in your case, it is).

I've never had much luck feeding a new food alongside an existing food because most of the new food will end up on the tank bottom and fowl the water while the old food is quickly eaten. Once they have less desire to eat, they probably won't want to try anything new. In reference to the age of the fish, I've transitioned a very stubborn male Blue Dwarf Gourami who was 2 years old from brineshrimp to flakes with this method.

The survival instinct seems to kick in and they'll eat anything. A hungry fish is a healthy fish so if they're pecking around the tank looking for food, that's a good sign.

As an alternative to removing food from the tank for a few days, I've also found that soaking the flakes in water with a garlic clove (or garlic granules) for a few minutes before feeding has been effective at getting them interested in the food. The garlic flavour seems to make them much more interested in all foods including peas which I've previously struggled to get them to eat.

It's always best to feed a varied diet if possible because if you run out of one food, your fish will happily accept another. I try to rotate the diet of my Tropical Community Tank from Scallops, brineshrimp and mysis to algae wafers, flakes and peas. Once they've accepted the food, you should find they'll eat it more readily.

Finally, if you have large fish, you can prepare your own fish food which you can pack with far more exciting ingredients and help get them acclimatised for any food.

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