How to get an aggressive fish?

[aw661]

Hey guys
My current setup consists of a 20 gallon tall, it has two medium sized craws and and green sunfish. my question is how do I get my sunfish to have more aggressive tendencies, he eats 24 rosies every two weeks. He's tried to bite my while scraping algae but otherwise he just sits in his corner. please help

 

[Deadeye]

This fish is already probably unhappy in such a small tank. Go even smaller and it will really be pissed off.

Last I checked, when a fish is unnecessarily destroying feeders (especially ones that are unhealthy for the fish) and attacking the keeper that usually checks all the boxes.

Most predators tend to lie and wait for the food to come to them. They waste much less energy that way. It’s definitely not going to go very far if it only can move 3x its full grown body length.


Now, if you actually care about the fish’s well being there’s two great places to start:
1. Stop feeding Rosies (or any live). All you’re doing is risking parasitic infection. Live feeding really should be left to the fish that will only eat live, and a sunfish is far from that.
2. Get the fish a bigger tank. You wouldn’t keep a German shepherd locked in a bathroom and expect it to be an active or healthy animal.

 

[jjohnwm]

This fish is already probably unhappy in such a small tank. Go even smaller and it will really be pissed off....You wouldn’t keep a German shepherd locked in a bathroom and expect it to be an active or healthy animal.

No, but...it would likely be pretty aggressive...

 

[aw661]

This fish is already probably unhappy in such a small tank. Go even smaller and it will really be pissed off.

Last I checked, when a fish is unnecessarily destroying feeders (especially ones that are unhealthy for the fish) and attacking the keeper that usually checks all the boxes.

Most predators tend to lie and wait for the food to come to them. They waste much less energy that way. It’s definitely not going to go very far if it only can move 3x its full grown body length.


Now, if you actually care about the fish’s well being there’s two great places to start:
1. Stop feeding Rosies (or any live). All you’re doing is risking parasitic infection. Live feeding really should be left to the fish that will only eat live, and a sunfish is far from that.
2. Get the fish a bigger tank. You wouldn’t keep a German shepherd locked in a bathroom and expect it to be an active or healthy animal.

Look it’s a native tank all the plants in my tank are from the river so are my craws, yes my tank is small and I’m working on that part but sunfish in the wild eat little fish, Im gonna continue feeding him little fish

 

[Sassafras]

"Its diet can include aquatic insects and larvae, insects that fall into the water, crayfish, snails, other molluscs, turtle food, frogs, some small fish, fish eggs, bryozoans, zooplankton, other small invertebrates, and sometimes plant material. They are omnivores." Source animalia.bio

"Green sunfish are omnivores, which means they consume both plant and animal matter. They readily eat insects, larvae, zooplankton, eggs, snails, crawfish, and other small forage fish." Source: panfishnation.com

"I’ve had good success with diets comprised of approximately three quarters live foods (earthworms, blackworms, guppies, crickets, sowbugs) and a quarter cichlid pellets freeze dried and fresh prawn, and trout chow. In the warmer moths, I collect moths, beetles, tree crickets, and other insects around my outdoor lights each evening. The strong reaction of my sunfishes (and, indeed, most tropical fishes) to these novel foods always fascinates me.
I’ve observed wild and captive Bluegills feeding upon aquatic grasses, so some experimentation with plant foods for other species may be worthwhile." Source: thatfishplace