Hole in the head is a common disease and is caused by a lack of certain elements/vitamins in their food. Most experienced aquarists feed their fish at least some live food every few days or so (at least once a week) to avoid this problem. Chopped finely or whole, depending on the size of the fish, and the size of the worm the best possible live food is earthworms. You would also need to be observing the basic rules of fishkeeping which are, :- 1 inch of fish needs a minimum of 1 gallon of water. :- Every tank needs a permanently running cycled filter. :- Every tank needs to have at least 50% of its water changed every week. Follow the above rules and your fish stand a chance of survival. Fail to follow them, and I can guarantee your fish will have constant health problems.
Yes, the whole fish will rot.
It can and will if left to rot in the water.
After death and before the corpse begins to rot.
rot
Bacterial infections like fin rot, mouth rot or body sores can make the fish rot. If the fins begin to get cloudy or milky and begin to rot, use a 0.3% salt solution into the tank. If the mouth begins to rot, this is usually caused by a parasite but also occurs from an overstocked tank. Remove the goldfish and place it in a more spacious environment and swab its lesions with hydrogen peroxide and inject it with an antimicrobial. Use the 0.3% salt solution and hydrogen peroxide on the body sores.
Albacore, anchovy, angel fishThe Angler fish.
because the fish would dry out and would rot out in the sun
Fin Rot. black ick ammonia burns. fish lice u name it google fish diseases
The bacteria on the meat begins to grow over time. With a large population of bacteria eating at the meat it begins to look and smell bad which marks the start of the rotting process. If you continue to let this meat rot eventually maggots will grow and hatch on the meat.
Jackfish
This can be caused by "fin nipping" between other fish or fin rot, which is caused by keeping fish in poor conditions.
the answer to the European fresh water fish that begins with r is Rudd