Please Someone Help My Fish!

Here are the photos of all my fish in the tank and the sick one. Also for the picture of the toddler oranda that looks like he or she is sucking food of the moss ball ; the photo description should say; The oranda has a little part on the end of his tail that looks like it came of and the part that surrounds it is white. Do you know what it is?

For the photo with the toddler oranda with a big stomach that is almost upside down looking like he is sucking food of the moss ball, the disscription should say ; There is a little piece of the end of his tail that looks like it came of and the skin that surrounds it is white. Do you know what it is? Also it is starting to look the the bubble eye fish is getting a white chunk like that too. Please help!

 

I am not entirely sure what your asking for in this post but here is what I noticed:

Your tank is wayyyy to small to be housing goldfish. They need Atleast 30g per goldfish. The white stuff looks like fin rot and the black edges are ammonia burn.

Is your tank cycled??
What are your parameters??

My feeling is that it is either not cycled or it is so overstocked that it can't keep up.
Also bettas shouldn't really be with goldfish, because goldfish require hard colder water with high ph and bettas require warm water with medium soft water and lower ph.

Sorry for being blunt but if what your asking is what's wrong with your fish and how to fix it then this is what I have to say.

Again I am confused as to what your asking so correct me if I am mistaken

 

Looks like the scales are protruding, which is a sign of dropsy. The tail looks normal for an oranda. This is a temporary tank, right? What are the parameters, temperature, and size of the other tank? Current?

 

This is totally confusing. What are all these pics?

 

Looks like they are reposting relevant info to the current on going problem using pictures, the bottom picture of text should also be above the top picture of text as it didn't fit on the same screen.