Yep, that's a Monotrete palembangensis (old: Tetraodon) or humpback or dragon or black river puffer. It's a full FW species. It's a stalk and ambush predator that can be disastrous in comm setups since even a test bite can kill. However, it's not overly aggressive with other palembangs in the tank. Be sure to provide lots of caves and rock/driftwood overhangs. Good visual breaks between caves will also help reduce interspecies aggression. Sensitive to water quality and a messy eater so, overfiltration is a must to keep this species happy. Can be treated with salt and increased temp for fungal infections.