Goldfish Nutrition/Gel Food Information
From my reading so far, I don't believe that feeding pellets or flakes exclusively is a healthy diet for goldfish. If you feed pellets or flakes, I think you should also add veggies and fruits to their diet. Pellets and flakes are highly processed foods and most contain cheaper and less digestable grain or soy proteins, fish proteins, and starch with added vitamins. If you read the ingredient list, and you see things like corn gluten, corn meal and corn middlings, that's called ingredient splitting. Fish food manufacturers do this because protein from grains/soy is cheaper and it makes the fish or shrimp protein look like it's the largest ingredient since it's first on the ingredient list. Feeding your goldies only pellets or flakes would be like you or I eating only fish sandwiches and multivitamins every day. The soy/grains in commercial foods also contain starches that goldies can't digest and that can feed gas producing bacteria in the GI tract which can cause bouyancy issues (flipping--often called swimbladder).
If your goldie is flipping, I'd recommend:
I'm feeding my goldies gel food with added acidophilus in the morning, and for dinner they get a 1 to 3 ratio of cocktail shrimp or krill and green beans, green peas and lima beans. I defrost the frozen foods in tank water warmed in the microwave, peel and break into bite sized pieces. You can find bags of small frozen cocktail shrimp very cheap at the grocery store. Bags of frozen veggies are also inexpensive. Sometimes I stick 1/4 of a zucchini in the tank for them to munch on at will. and sometimes they get live redworms from my worm composter or live daphnia. They also get some duckweed, azolla and frogbit plants to munch on daily. Occasionally I feed kiwi for a lunchtime snack high in vitamin C or put a quarter of an orange in the tank.
This diet has worked wonders for my big moor Lumpy who flipped in response to eating flakes and algae wafers. I'm hopeful that at some point pellets or flakes could be added back to the diet after the intestional flora has been altered. That still remains to be seen. Note: I've been feeding the acidophilus gel for several months now, and Lumpy still gets floaty if I feed pellets too often.
Goldies don't have a stomach like we do, so it's best to feed frequent smaller meals. Here's a couple of necropsy pics (1, 2) that shows the swim bladder and GI tract. Feed too much and it comes out the back end only partially digested.
Fish Nutrition Links
Gel food recipes and their nutritional content
Below are some recipes for gel food. Some are mine. Some were developed by other people. I've included links to the recipes where I've worked out the nutritional content.
I usually shoot for around 50% protein in my gel cuz the veggies also contribute protein, but it's less digestable protein. I try to make sure I use a fatty fish (e.g. mackerel, lake trout, herring, sardines, albacore tuna or salmon) that contains all the essential amino and fatty acids. I also add flaxseed oil to bump up the amount of essential fatty acids and try and keep total fats at around 10%. I use green and red veggies for the most part in the gel and shoot for a mix of around 50% protein with the carbs being mostly complex carbs and fiber, to try and keep the simple sugars fairly low.
Nutritional content of:
Foods sorted by their nutritional content: