its a european carp ,they are related to gold fish, hope you didnt relese it, they are a pest and must be killed
from DPI website:
What to do if you catch a tilapia or carp
If you catch a noxious fish, kill the fish as quickly and humanely as possible. Fisheries Queensland advocates following ethical euthanasia protocols recommended by the 2001 ANZCCART publication - Euthanasia of Animals Used for Scientific Purposes. The most appropriate method may involve stunning the fish via a sharp blow to the back of the head followed by brain destruction.
It is an offence to have noxious fish (such as carp and tilapia) in your possession, dead or alive (except dead Nile perch). You must therefore dispose of the fish as soon as practicable after killing. It is recommended that you do this by burying it a suitable distance from the waterway where it was caught or disposing of it in a rubbish bin.