Science project

Do Crushed Peas Cure Swim Bladder's Disease in Goldfish?

Research Questions:

Have you ever wondered why humans cannot nearly stay in the water as long as fish do? Yes the fish have gills, fins, and are cold-blooded, but they also have a swim bladder. The swim bladder is a tiny sac in the anterior abdomen of the fish which maintains its buoyancy.

If there is something wrong with the swim bladder, the fish will not be able to stay in the water correctly--they will either float on the surface (some people mistake this for a dead fish, but it is NOT dead!) and some stay on the bottom and cannot seem to easily float back up.

Some possible causes of swim bladder disease is poor water quality and the way food is taken in by the fish. Swim Bladder's disease should be treated promptly or else it will result in dead fish. Some say that crushed peas do the trick. In this experiment, we'll find out.


  • Goldfish with Swim Bladder's Disease (Swim Bladder's Disease is relatively common among goldfish so perhaps someone you know have goldfish who needs help or ask your local aquarium/fish store)
  • Fish tank w/ filter
  • Water
  • Peas (frozen, fresh, or canned)
  • Pen and paper for notes

Experimental Procedure:

  1. Put the goldfish with swim bladder disease in a filtered tank.
  2. You should observe the goldfish swimming awkwardly, floating on top, or stuck on the bottom.
  3. Soften up some peas. These peas can be frozen, canned, or fresh. If they are not cooked, make sure to cook them!
  4. Take the peel off the peas and mash them up to a not-too-mushy but not-too-hard consistency.
  5. Drop a small amount of mashed peas into the fish tank.
  6. Observe as your fish eats it.
  7. Feed the fish the mashed peas (and nothing else!) for a week. Observe daily progress.

Going Above and Beyond

There are other methods to cure swim bladder disease. Try comparing the pea-diet method above with the fish-fasting method (in which you do not feed your fish for a couple of days), and the needle method (not to be taken lightly, should be done with experienced hands).



Notes & Observations

Day 1




Day 2




Day 3




Day 4




Day 5




Day 6




Day 7 (1 week)





Terms/Concepts: Swim bladder disease;  Goldfish care; Tank water quality; Underwater buoyancy


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