Physical injury or fin rot?

[Litchi]

I have been taking care of a male betta for about 3 weeks now and have noticed that one of his ventral fin seems to be disappearing. Initially when I brought him one of his fins seemed bent so I thought it must be a an injury/ fin curling as he was kept in a very small tank. But recently I have noticed that both his ventral fin is bent and now the previous fin that I thought that it may be injured now looks like two threads. Other than this, he is very active, is feeding well, creates bubble nests often but he seems to be swimming a lot near the surface lately. I currently keep him in a 1 gallon tank(Sorry but I am trying to get him a better tank), do water changes about 50% every other day. Since I read that rock salt may act as a water conditioner, I tried adding some(about less than 1/2 a teaspoon) and also added ampicillin thinking it might be fish rot. I also cleaned all the gravel. I am still so scared. What am I supposed to do? I have attached the pics when I initially brought him in and now. Kindly give your suggestions regarding this.

 

[Bruce Leyland-Jones]

Having seen the small bowl your fish is currently in, you are doing well to get him a bigger tank, immediately. Those 'bubble nests' are more likely your fish trying to breathe, whilst swimming in his own toilet.
Your fish will be stressed and will literally fall apart! Without rocks, you'll also be more able to remove any fish waste from the tank, when you change the water.


To begin with, remove those rocks from the bowl, to give the fish more space.
An aerator, with an airstone would not go amiss. I know Betta are labyrinth fish and can survive in small spaces, but they don't do well in such conditions. Aerating the water will give your fish another much-needed boost.
Adding a small bunch of plants would also be a good idea, to give the little one some security.

Your water changes are good, but be sure to add water conditioner when you add new water.

I'll also assume that you didn't cycle the bowl before adding the fish? This means that there's no beneficial bacteria in there, to digest the fish waste/ammonia.

 

[Litchi]

Having seen the small bowl your fish is currently in, you are doing well to get him a bigger tank, immediately. Those 'bubble nests' are more likely your fish trying to breathe, whilst swimming in his own toilet.
Your fish will be stressed and will literally fall apart! Without rocks, you'll also be more able to remove any fish waste from the tank, when you change the water.


To begin with, remove those rocks from the bowl, to give the fish more space.
An aerator, with an airstone would not go amiss. I know Betta are labyrinth fish and can survive in small spaces, but they don't do well in such conditions. Aerating the water will give your fish another much-needed boost.
Adding a small bunch of plants would also be a good idea, to give the little one some security.

Your water changes are good, but be sure to add water conditioner when you add new water.

I'll also assume that you didn't cycle the bowl before adding the fish? This means that there's no beneficial bacteria in there, to digest the fish waste/ammonia.

Thank you! I ll make sure to follow them.