3.4. Gel Fish Food

The food I used for my fish is a homemade high protein gel fish food. I find this to be the healthiest food there is as the protein level is very high, >55% by dry weight. The Mazuri gel food is also excellent.

Many hobbyists like to make their own food. So here is one recipe for doing that. Note that there are many ways to vary this and none are the “right” way.

To make one variation of gel tropical fish food get the following ingredients:

• one pound (16 ounces cut up into ½ inch pieces) drained raw or cooked meat. Canned salmon is the best, especially for breeding fish. But any fish fillet, shrimp, chicken or lean beef is fine, as is beef heart, chicken livers or chicken hearts. Even canned tuna in water is just fine (Just drain the water). Some add fish meal or krill meal, both of which are excellent.
• One to two ounces of dry powdered algae (spirulina or chlorella, the green smoothie craze has made these easily available). Alternatives include peas, beans, summer squash, green beans and zucchini.
• One and one half ounces of plain gelatin (this is six envelopes of Knox gelatin). Note that, while gelatin is preferred (70% digestible protein), pectin or agar can be substituted for the gelatin.

Heat the meat and algae to hot.  Then heat one cup water to boiling. Add one and one half ounce of gelatin powder to the one cup of water.  Stir the gelatin/boiling water mixture till the gelatin dissolves. Let both mixtures cool till they are safe to handle but still very hot. Then put both the hot gelatin/water and the hot algae/meat in a blender. Blend all this thoroughly to make a hot viscous green putty-like material. Adjust the water content to get this wet putty consistency.

This hot viscous putty should then be solidified as 3 mm (1/8 inch) thick slabs in zip lock bags in a freezer. It is important that the gel food be a thin slab. A thin slab is easy to break up and will rapidly defrost and break up in the water. Alternatively one can use candy molds to make cubes or whatever shape one desires. Or you can put it in baking pans or plastic tubs and just cut cubes out as you need them.

This well gelled cold material can be just used as is, just cutting off or breaking off and chopping up what is needed for each feeding. Chop up the gel into smaller pieces.  Large hunks of gel can be monopolized by dominant fish, especially in growing fish. When feeding break up the food clump in the aquarium and let the food particles flow out over the whole aquarium, this is very important.

Note that this is a very flexible recipe. If one has some leftover vegetables like cooked zucchini, summer squash, green beans, etc. or shrimp or chicken, ad. infinitum. just toss it in. I do avoid kale, broccoli, cauliflower, and cabbage as they make the aquarium smell bad,

And avoid spinach.  I made this recipe for many years using spinach instead of algae. Then Dr. Richmond Loh found oxalic acid (spinach is very rich in oxalic acid) crystals inside the organs of some fish that had died from bloat after eating a spinach based recipe. Given the wide availability of the powdered algae it just seemed wise to switch away from the spinach.

The amount of gelatin in this recipe is designed to give a firm gel that requires fish to “chomp” on the food to eat it. I find this tends to minimize food clouding up the water with small particles.  But if you want a softer gel simply reduce the amount of gelatin in the next recipe you mix up.

This gel food sinks in the aquarium. If you want a gel food that floats simply add a heaping tablespoon or so of whipped cream or Reddiwhip to the final mix.

Juvenile fish need fat, calcium and phosphorus in order to have good growth. So if one is feeding juvenile fish, add one fourth teaspoon steamed bone meal (get from a garden store) and three tablespoons cod liver oil (from the internet or a health food store) to the blender before blending. Note this isn’t necessary with the canned salmon as it has bones and oil in it and is a super fish food for juveniles, especially after thorough blending on high speed.

If you are breeding fish they need 10% to 15% fat BY DRY WEIGHT in their food. This can be supplied by any fat or oil.  Salmon, chicken and beef heart are reasonably  rich in fat.

It may be wise to add a small amount of powdered astaxanthin to this gel food. This is a harmless material that adds red pigment to any fish without affecting them. It is the red color in flamingos. If you have red or orange fish this may  or may not be important. Add just ¼ teaspoon of astaxanthin to the blender (obtain from the internet or health food store). Note that one can add other “color enhancers” such as powdered spirulina, paprika and marigold powder if one desires. Also note that too much astaxanthin can produce very dark fish colors. Also note that some yellow fish turn orange with high astaxanthin.

Note adding vitamins is not recommended. If the food has spinach or other green vegetable in it, it will have more than adequate vitamin content.

This gel food is very high in protein. By DRY WEIGHT it is 55% to 65% protein. The calculations for this are that canned salmon is 13 grams protein per 55 grams of canned salmon. Canned salmon is probably 60% water, 40% DRY fish meat. 40% of 55 is 22 grams. 13 divided by 22 is 59%. In other words, by DRY WEIGHT 59% of the can is protein. Surprisingly algae is almost as rich in protein by DRY WEIGHT. This high protein level is great for fish and for the ecology of the aquarium.

Also note garlic is NOT a good additive for fish food. The sulfurous compounds in garlic are there to make the garlic LESS palatable to animals. No aquaculture operation adds garlic to get the fish to eat more. So it just doesn’t work. It is the common practice of anthropomorphism, making animals human.

Here is an actual comment about this gel food:

“I have made the Gel Food following your recipe to the tee. Used Agar instead of Gelatin. It has become the most liked food for my fish, even for bottom feeding Plecos. Some even ignore live food and crazily devours this Gel. It’s just awesome.”

University of Florida Recipe

This is a recipe from the University of Florida (“A Comparison of Metronidazole Treatments for Hexamitiasis in Angelfish”, Whaley et. al. 1991) which closely parallels my recipe:

Recipe for Gelatinized Food

• 6 oz  Can of Shrimp
• 2 oz  Frozen Spinach
• 1 oz  Grated Carrots
• 3 tbsp         Baby Cereal (dry)
• 2.5 tbsp      Brewer’s Yeast
• 2 oz  Unflavored Gelatin
• 15 oz Water

Procedure

• Blend 5 oz of water with shrimp, spinach, carrots and brewer’s yeast
• Boil remaining 10 oz of water.
• Add boiling water to gelatin in a bowl.
• Cool until gelatin mixture is hot but doesn’t burn.
• Add contents of blender to partially cooled gelatin mixture, mix thoroughly.
• Pour into flat pan and refrigerate.
• When mixture has gelatinized, cut into cubes for feeding and store in freezer.

I’m not a fan of using cereal in any fish food. And a root crop such as carrots does not reflect what fish should be eating. But this recipe will work well for any fish.

Mazuri Gel Food

A reader told me about a commercial gel food which is excellent. It is Purina’s “Mazuri® Aquatic Gel Diet for Carnivorous Fish”. It is VERY easy to make up without any blenders and the like and has a VERY good analysis.

• Crude protein not less than ….. 56.0%
• Crude fat not less than ………….15.0%
• Crude fiber not more than ……… 5.0%
• Moisture not more than ……….. 12.0%
• Ash not more than……………….. 15.0%

At $28.99 per kilogram the food is very reasonably priced. It is impressive! It will work well as a fish food for ANY fish. It is prepared by simply adding hot water and mixing. Put the mix into the refrigerator to gel it.

Note if one has a mixed tank one might feel more comfortable adding roughly one fourth powdered spirulina or chlorella to the Mazuri powder. These powders are now readily available at reasonable prices due to the green smoothie rage. This will bring down the fat level to about 12%, which is optimum for fish breeding. And it adds some veggies to the meat in this product.

Repashy Gel Food

There is a commercial gel food called “Repashy”. This is an analysis for “Repashy Soilent Green”

• Crude Protein  … 40% min
• Crude Fat ………  8% min
• Crude Fiber ….…. 8% max
• Moisture………….. 8% max
• Ash ………………12% max

Considering this food costs an eye popping $150 per kilogram and the analysis is not great I really cannot recommend it.

The Easy Alternative

If you don’t want to go to this bother just chop up fish fillets or shrimp into small pieces of suitable size for the fish you are feeding. Add zucchini slices to the aquarium occasionally, impaled on a fork or tied to a rock. If you must have dry food sitting by the aquarium for convenience, use freeze dried brine shrimp, tubifex worms or krill for feeding.

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