Is my tank big enough for what i have?

Erm, if you got rid of the shark and the clown loach, you *might* be set. If it's an oscar from bigger stock, it could grow to 10 inches, and some will only grow to 6. Clown loaches get to a foot, and plecos 8 inches. So yes, donate the shark and the clown loach, or you will have a sickly, dwarfed oscar.

*Suggestion* Get rid of the shark, they need to be kept in groups of 5 or more, which would require a 500+ Gallon aquarium.

No...

A 55 gallon tank is only suitable for one JUVENILE oscar. Within a year it will reach it's adult size and will need at least a 75 gallon tank.

Plecos get HUGE. A foot and half or more. They need nothing less than 100 gallons.

The shark will also get big, and needs a larger tank.

And clown loaches are schooling fish. If you want to keep them, you need AT LEAST 4.

Even if you get rid of the shark, you are FAR from being set.

no. you wouldnt be set. the small oscar will need 75 gallons of water to itself at adulthood. the clown loach will get 14 inches. the plecos going to get even bigger. the shark will get bigger. go get a 500 gallon tank.

Eventually you will need an even bigger tank for the oscar the pleco and the shark.

According to Aqadvisor.com this is what your tank is before removing the shark

Warning: Oscar is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 12 inches.

Note: Clown Loach may pretend to be dead at times.

Warning: Clown Loach is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 12 inches.

Warning: At least 5 x Clown Loach are recommended in a group.

Warning: Iridescent Shark is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 36 inches.

Warning: At least 5 x Iridescent Shark are recommended in a group.

Note: Common Pleco needs driftwood.

Warning: Common Pleco is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 18 inches.

Warning: Your selected species may eventually require 129% of your aquarium space. You may need to deal with territorial aggressions later on. Try removing some of (Astronotus ocellatus, Chromobotia macracanthus, Pterygoplichthys pardalis) or get a larger aquarium tank.

Recommended temperature range: 24 - 26 C. [Display in Farenheit]

Recommended pH range: 6.4 - 7.5.

Recommended hardness range: 5 - 15 dH.

You have not selected any filters - select one or enter a User Defined value.

Your aquarium stocking level is 254%. [Generate Image]Help on Generate Image

Your tank is seriously overstocked. Unless this setup is temporary, you should consider a larger tank.

and this is what they say after removing the shark

Warning: Oscar is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 12 inches.

Note: Clown Loach may pretend to be dead at times.

Warning: Clown Loach is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 12 inches.

Warning: At least 5 x Clown Loach are recommended in a group.

Note: Common Pleco needs driftwood.

Warning: Common Pleco is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 18 inches.

Warning: Your selected species may eventually require 129% of your aquarium space. You may need to deal with territorial aggressions later on. Try removing some of (Astronotus ocellatus, Chromobotia macracanthus, Pterygoplichthys pardalis) or get a larger aquarium tank.

Recommended temperature range: 24 - 27 C. [Display in Farenheit]

Recommended pH range: 6.4 - 7.5.

Recommended hardness range: 5 - 15 dH.

You have not selected any filters - select one or enter a User Defined value.

Your aquarium stocking level is 159%. [Generate Image]Help on Generate Image

this tank is only large enough for the oscars. unless you can buy a larger tank in the near future, no its not bug enough. sorry