The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Feed food that will sink to the bottom. Maybe your fish will be able to grab some and get make to a healthy size. But it looks very skinny and unhealthy right now.
I use a steak injector to get food into my gobys mouth it took some training but it works. Your guy is really skinny I would find a way to spot feed ASAP.