Mini Predators for a 20L/29 gallon?

[ichthyogeek]

Are there any piscivorous mini predators that work in a 20L/29 gallon tank? I'm looking for a fish that would coexist with LPS like Trachyphyllias, eat fish up to 3" long (culls from various breeding projects), but is easily trained to eat frozen. I know with a 55 I could go with some sort of dwarf lionfish, but I'm not well versed with other predatory fish.

Although I guess I could break out the 100 gallon pond tub thing....but I'm trying to reserve that for growouts...

 

[lion king]

Most of the little predators I know would likely need to be fed live foods. Some will take dead but it is never guaranteed and the commitment to the right dead foods are more of a pita than feeding live. The Caribbean scorp gets to about 4" and takes dead food pretty easily, and is a really cool fish. The wartskin angler would fit nicely but is usually difficult to get to take dead food consistently. A couple of waspfish stay pretty small, like the longspined and cockatoo, and have been known to take to dead foods. Again I must stress it's not just about getting these fish to take dead food, it's about feeding the right foods. I would never say these type of fish are "easy" to take to dead food.

 

[Coralsdaily]

This is your guy!

 

[Han]

What about an aggressive fish eating invert, like a reef lobster or mantis shrimp?

 

[Tired]

If you're looking to dispose of fish humanely, clove oil euthanization is a good method. Then you can do something like bury them outdoors as plant fertilizer. I wouldn't really suggest getting a predatory fish specifically to kill other fish with, it's not a very humane method of killing something.

Just to have a cool predatory fish, rooster waspfish are good. Mine took frozen happily. They won't eat fish that size, though, they barely get past 3" themselves.

 

[ichthyogeek]

What about an aggressive fish eating invert, like a reef lobster or mantis shrimp?

A mantis shrimp totally passed my mind, I think I'd have to do some more research, but it's definitely on the table for now!

 

[ichthyogeek]

If you're looking to dispose of fish humanely, clove oil euthanization is a good method. Then you can do something like bury them outdoors as plant fertilizer. I wouldn't really suggest getting a predatory fish specifically to kill other fish with, it's not a very humane method of killing something.

Just to have a cool predatory fish, rooster waspfish are good. Mine took frozen happily. They won't eat fish that size, though, they barely get past 3" themselves.

That's true. I'm not sure if where I'm moving will have an outdoors for me to use, and throwing them in the trash seems incredibly wasteful. Ideally, I'd euthanize the fish first before feeding, but from what I understand, anesthetics like clove oil aren't healthy for predatory fish to ingest.

 

[Han]

I’ve fed ded fish to my lobster, I always euthanize first though if they’re not already dead. I definitely wouldn’t use clove oil, there are other humane ways to euthanize fish.

 

[Tired]

Clove oil is about the best method you can easily get, though. There are inhalable anesthetics you can get, but those can be expensive, and aren't exactly available at the local grocery store. Freezing is NOT considered a humane method to use on fish. Pithing (physically destroying the brain) is quick and effective, but difficult to do on small animals.
Though if you could figure out an effective physical method of killing the cull fish, those would make good food. They could then be chopped up, as well, to feed a smaller predator.

As for what to do with hypothetical clove-oil-euthanized ones, I suppose you could try to make friends with someone who does have an outdoors. Then you could freeze the culls, and now and then give the culls to them to bury outside.
How many culls do you expect to have? Large houseplants could work for just a few, or for little ones. Plants love bone and blood meal, and they love fish meal, I expect they'd love entire fish as well.

And, if it came down to it, humanely killing them and throwing them in the trash would mean that flies and other bugs would get them at some point. I doubt much food in landfills actually just gets buried and entombed forever- they're probably just laden with bugs. Nature doesn't leave available food alone.

 

[Picasso the Triggerfish]

If you could make your tank 70 gallons or more you could perhaps consider a hamlet, which is a small species of grouper and grows to about 6 inches long.

However, if you can't, then consider a spearer mantis or another predatory invert like a cephalopod (if you go for a cephalopod, place a really thigt fitting lid, they are escape artists)