What are these pellet products you got, Sergio? What fancy goldfish do you have?
I keep mostly fancy goldfish myself. The first thing we have to remember is most of the fancy goldfish have a very compact appearance which also implies their body organs are greatly compressed as a result of that done by selective breeding. In this case, digestion becomes a little more awkward hence most of the cases involve goldfish suffering from buoyancy issues, bloat or constipation.
In connection to the above paragraph, we need to include a big portion of high fiber in their diet. This can be done by feeding them vegetable matter and extra aquarium plant cuttings which are very high in fiber. If possible, make gel foods and use baby foods that are purely vegetable matter. Be very careful with the ingredients you choose. Some vegetables such as broccolis and brussel sprouts produce gas and those can likely cause buoyancy issues if the goldfish are overfed with those stuff. You could simply stick to pears, collards, dill greens and peas.
A lot of commercial foods have very low fiber. I don't think of all the food products I tried to compile, one ever has the right fiber content. They are mostly focused on protein content unfortunately and while very low fiber content is good for reducing pollution, it discourages the goldfish from expelling the trapped wastes inside their GI (gastrointestinal) tract.
Secondly, a lot of foods contain the rubbish fillers (starch). Starch is also responsible for producing gases inside the GI tract. You must make sure your choice of food does not comprise a bigger portion of starch-based ingredients especially if the top ten slots on the ingredients list contain more than 3 starch-based ingredients with one starch-based ingredient taking up the top spot. I go for food products where the first ingredient should be anything other than a starch-based ingredient.
I feed my own goldfish Hikari Lionhead, homemade gel foods, Mazuri gel foods, aquarium plants, frozen stuffs and many more. What I avoid are freeze-dried stuffs and commercial foods that contain too muc starch. Floating types are also avoided. Pond type goldfish such as shubunkins would not have issues with any of those foods but as fancy ones have a lot of issues compared to the pond types, the problematic ones have to be avoided at all costs to minimize the issues as much as possible.
Assuming your goldfish are still very young, you could aim for at least 40-60% protein content. The Mazuri 5M70 caters to that. Unfortunately, Mazuri gel foods, like other commercial foods, have very low fiber content at 2% so it is best you add vegetable matter in their diet. Adult goldfish will need not more than 30% of the total protein content as it simply adds up only to pollution since they cannot fully utilize the protein for body and wen development.
Lastly, I add acidophilus in my gel food recipes to help cut down the possible gas that may be produce by the goldfish as they eat almost anything. It is available in health stores. It is not a necessity if you are avoiding foods that contain too much starch or are floating types but it can help as a precaution.
Hope this helps.
Lupes
