Yes. Aslong as the gold fish (coldwater fish) and the pleco (warm water fish) do not go into one extreme or the other on the temperature scale. Your Plecostomus will look like it is eating your goldfish if it doesn't get enough food.
yes
Daphnia live in lakes, ponds, slow moving streams.
No, Daphnia cannot live in an aquarium with fish as they are likely to be eaten by the fish.
No. Goldfish are freshwater fish and tropical starfish are saltwater fish.
Daphnia prefer 64-72 degrees Fahrenheit.
Goldfish and cichlids have different care requirements and temperaments, so they may not live peacefully together in the same aquarium. It is generally not recommended to keep them together.
The best thing to do is ask the shopkeeper in the fish shop and find out first but goldfish go together with no problems if you are lucky because some goldfish can't live together. http://en.wikipedia.org/wiki/Goldfish
500 years
Flake, Pellet, Tubiflex, Krill, Plankton, Brine shrimp, Blood Worms, Spirulina, and Daphnia
The number of goldfish that can live together in a single tank depends on the size of the tank and the type of goldfish. In general, it is recommended to have 20 gallons of water per goldfish to ensure they have enough space to swim and thrive. It is best to research the specific needs of the type of goldfish you have and consult with a pet store or veterinarian for guidance on the appropriate number for your tank.
no turtles will eat any fish they can catch
Yes they can. I raised them together many times.