I have a 25 gallon fresh water tank with One Marble Angel - size 3", One White Angel - 2",2 Gold Fishes-3" each, and a Black Shark-4". What other fishes and how much, that i can keep along with these. Please,suggest
You're already overstocked. You should only ever stock a tank based on adult sizes and compatibility.
Goldfish are NOT compatible with Angelfish or Black Sharks. Depending on what kind of Goldfish you have they will eventually get between 6"-12" in length and need a cooler system than Angelfish who need high end tropical. Goldfish are also bullies and fin nippers and can damage the Angelfish.
A pair of Angelfish need more like 40 gallons plus and will get between 10"-12" in height - they need a tank a minimum of 18" tall.
As for that Black Shark, if it's a Red Tail Black Shark it will get about 6" and highly territorial - they need more like 35-55 gallons as they are very active. If it's a Labeo chrysophekadion Black Shark then you're in trouble as these guys get over 12" and are evil beasts, they'd destroy Angelfish and Goldfish and should only be kept with fish of similar size in tanks over 6ft long, not a 25g!
In that tank I wouldn't be thinking of adding anything, rather I would be rehoming fish and doing proper species research!
Marbled Angel fish,Gold Fishes, and the Black Sharks are fresh water fishes so you can get anything that is freshwater.
Try guppies they live a long time.
guppies and angels can fin nip even though they are considered peaful. i hear its something to do with jealousy of big fins. whatever.
anyway i would say you wouldn't rally want any more fish in there, especially with the gold fish in they will be getting too big for that tank without any other fish in
if you must put another fish in, try corydorys catfish, small pretty bottom dwellers and always busy! albino ones are interestingly strange looking and i have a sterbai cory he is speckled with bright orange fins and they never grow that big, and will always look for food so fresh leftover food is usually cleaned up