The tail fin is crooked, likely to be caused by previous injuries. As the fin rays were injured, it may be tricky to recover this.
slight melting on the edge of fins indicates a below optimum environment. If fish is new to your tank, it is likely the previous environment is no good. Improving water quality can help recovery for this issue.
not very likely to retain the golden head in your tank environment.
P/S: is that a dorado in the first pic? Is it attacking your arowana? chewing on its fins?
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