|o What types of food SHOULD we feed our fish?
o Do foods certain food types/brands produce healthier fish?
o Should foods change with the season?
o What is the best food for babies?
o Do you recommend color enhancer types of foods?
What types of food SHOULD we feed our fish?
I think the smart hobbyist would feed two, good quality pelleted foods, mixed together. The reason I say this is because people who make foods try and put good stuff into the foods but sometimes, to keep costs down, they skrimp. And they might leave out an essential amino acid or three. So when you mix two good foods, you are probably compensating any small deficiency in one (or the other) food as far as balance.
People say you should not feed pelleted food, "too much carbs", or not digestible enough. This is craziness. They're carp after all and they're the "shell-crushing mud-sifting omnivore of the world". Wonderful at making do with not-much.
However, in the evaluation of food, consideration should be given to the source of the protein in the diet.
Plant protein is not as good as terrestrial animal, muscle protein. (Chicjken and beef)
Muscle protein from mammals is NO WHERE NEAR as good for fish as FISH proteins are.
So, the best proteins for fish happen to be shrimp, fish or other maritime (aquacultural) proteins.
Look for fish, or shrimp as the first or second ingredient of a well formulated food. And don't get 'snowed' when the pundits talk "digestability" - because that's NOTHING compared to the ability of the fish to digest and THEN ASSIMILATE the proteins. It's easy to digest many proteins, but whether the cells will actually pick up those proteins and assimilate them, that's another deal altogether.
Mixed pellets then - and then treats. Shrimp, krill, fruit, vegetables, silkworm pupae - all are good for Koi. Earthworms are also good for Koi but some won't eat them. You don't have to drown the worms to get the soil out - there's no harm in it. Or go ahead and drown the worms, to get the soil out, there's no harm in that either.
Do foods certain food types/brands produce healthier fish?
Yes. GoldKist foods produce healthy fish on the short term. So do Rangen commercial foods - but for the long term, the higher quality proteins should be selected. The more fishy the proteins, the better your fish will do. Also, watch out for the feeding of super high (30+) percent protein for the long term. Fish don't want or need that much, except MAYBE in the rapid small-fish growth phase.
I REALLY like Sho Koi, Medicarp, Dianichi and Hikari as my "top four", if pressed to say so. (If money was no object! Some of these are VERY expensive!)
Should foods change with the season?
Not really. They CAN - I mean, there's no harm in doing a specific job on the food per season - that's fine. But I don't want anyone to think they HAVE to. Feeding a diet with less residue (more carbs) in the colder months might be a good idea. It's easier to digest and there's less bulk in the GI ttract while it's "cold" and working inefficiently. You ought to stop feeding if the water temperatures drop below 55 DF because the fish won't be digesting well, and the nitrogen reducing bacteria will be on hiatus in cold water like that so Ammonia will accumulate.
What is the best food for babies?
Probably blood meal - for starters, but you can use boiled egg pureed in water - and there are also commercial "fry foods" you can use. Very quickly as they grow, Koi babies which are fed TetraMin's Tropical Fish Flake Food will grow rapidly and healthy. Then as soon as they can start to take it, buy one of the above four foods, (Sho Koi, Medicarp, Dianichi and Hikari ) and put this in a blender - making a "powder" - and feed that.
The problem with fry is that they CANNOT stand Ammonia accumulations or Nitrite.
So as you feed so heavily, water changes and impeccable nitrogen reduction in the filter is CRUCIAL. Or you'll be netting dead babies out every day. Be wary of cannibalism - it's the whole reason Showas (and the like) are so rare. Some fish grow much faster than others. Unculled, you will see that Ogons outgrow, then outcompete, and finally EAT the slower-growing gosanke.
Do you recommend color enhancer types of foods?
YES AND NO - Fish kept outside with *sunlight* and algae, green water, mud to sift through and live insects in the forage will not need any of those color enhancers. It will be up to the natural, varied diet PLUS solid genetics for color and the fish will be "all that" - color wise.
However, most fish aren't in that kind of sunny, mud bottomed pond, and not all fish have great genetics - so color enhancers are in fact helpful. Spirulina is nothing but algae - and it helps color, and there are shrimp oils that do wonderful things for reds. Synthetic color enhancers also work very well - in some cases too well. Pinking can result - but I've never seen that. The worst you get with EXCESSIVE color enhancers is yellow heads. I've never actually seen pinking although it's 'reported' - by some.
Dr Erik Johnson