• Understanding Compatibility,
• Food types,
• Water chemistry,
• Species behavior,
• Environmental.

For aquatic creatures, there is a wide variety of different food types available.  Generally speaking, if it’s organic and it’s in the water, it’s a food type.  Fish and other aquatic animals will consume just about anything that makes it’s way into the water.

From a compatibility standpoint, the food type used for the aquarium occupants should be palatable to all.  Trying to provide different food types for different species’ palates is a difficult task unless the food types are live and size differentiated.  A size differentiated food type will appeal to larger fish and not to smaller fish.  Consequently it might be possible to target a particular aquarium occupant with a type of food.

For the purposes of establishing compatibility, the aquarist should verify the aquarium occupants are able to consume the same food types.  A helpful tool in this process is the Food Type Quad Chart.  The chart allows the aquarist to plot the different types of food that are consumed by the existing aquarium occupants.  The aquarist then has the ability to see what food types are available for a potential addition to the aquarium.

To use the Food Type chart, the aquarist will identify the food types consumed by existing aquarium occupants by placing a mark for each occupant along the line emanating from the center of the chart and intersecting with the normalcy circle.  This is done for each occupant.  The result will be a series of dots along the circumference of the circle indicating what foods are consumed.

To determine compatibility the potential new occupant is likewise plotted in the chart to see if the food requirements match.

Following is a short discussion on food types commonly used for aquariums.  Some are added to the aquarium, and some develop in the aquarium over time.

Food flakes are generally available in most pet stores and are typically composed of a mixture of ingredients that provide essential nutrients for fish. The specific composition can vary depending on the brand and type of fish food, as different fish species have varying dietary requirements. Generally, they are composed of the following:

• Fish Meal: Fish meal is a primary source of protein in fish food flakes. It is made from ground-up fish and is rich in essential amino acids.
• Wheat Flour or Cornstarch: These ingredients are often used as binders to hold the flakes together.
• Soybean Meal: Soybean meal is another source of plant-based protein used in some fish food formulations.
• Fish Oil: Fish oil is a source of essential fatty acids, particularly omega-3 fatty acids, which are important for fish health.
• Wheat Germ: Wheat germ is a source of vitamins and minerals, including vitamin E.
• Spirulina: This blue-green algae is sometimes added to fish food for its rich nutrient profile, including vitamins, minerals, and pigments.
• Vitamins and Minerals: Various vitamins and minerals are added to ensure a balanced diet for the fish. These may include vitamin A, vitamin C, vitamin D, calcium, and others.
• Color Enhancers: Some fish food flakes contain additives to enhance the color of ornamental fish, such as carotenoids like astaxanthin.
• Preservatives: To extend the shelf life of the flakes, preservatives like ethoxyquin or vitamin C (ascorbic acid) may be included.
• Antioxidants: Antioxidants like BHT (butylated hydroxytoluene) can be added to help maintain the freshness of the product.
• Binders and Stabilizers: These are used to maintain the shape and texture of the flakes and can include ingredients like guar gum or agar.

Generally, fish flakes are available at most pet stores and Internet sellers. There is some variability in contents to more closely address nutrition requirements of different fish species.ntially incompatible species.

Plant Matter & Algae:  Plant matter and algae can be important components of fish diets, particularly for herbivorous and omnivorous fish species. These sources of food provide essential nutrients, fiber, and natural pigments.  Generally, plant matter can be any part of a plant that is either still attached to a living rooted plant, or material that has recently detached from a plant.

• Leafy Greens: Many herbivorous fish, such as certain species of cichlids and plecos, thrive on leafy greens like lettuce, spinach, and kale. These greens provide essential vitamins, minerals, and dietary fiber.
• Vegetable Slices: Cucumber, zucchini, and peas are often used as fish food. These vegetables are typically blanched or softened to make them more digestible for fish.
• Algae Wafers: Algae wafers are specially formulated fish food that contains a high proportion of plant-based ingredients like spirulina, algae, and various vegetables. They are designed for herbivorous and omnivorous fish.
• Seaweed Sheets: Some marine fish, like tangs and surgeonfish, require seaweed or algae sheets as a significant part of their diet. These sheets can be attached to clips inside the aquarium.
• Aquatic Plants: In aquariums with live plants, fish may nibble on the plants. While this is not their primary source of food, it can supplement their diet and provide natural grazing opportunities.

Initially this food source is difficult to provide in a new aquarium.  However after a month or so, there will be ample plant matter and algae to support occupants who favor this food element.

Invertebrates: Invertebrates are a common and highly nutritious source of food for many fish species, both in the wild and in aquariums. Invertebrates encompass a wide range of organisms that lack a vertebral column, including various types of aquatic animals and insects. They are an essential part of the natural diet for many fish species and can be used to supplement the diets of fish in aquariums.

• Brine Shrimp (Artemia): Brine shrimp are tiny aquatic crustaceans that are commonly used as live or frozen fish food. They are rich in protein and are particularly suitable for feeding small fish, fry, and picky eaters. Brine shrimp are often hatched from cysts and used as live baby fish food.
•  Daphnia: Daphnia, often referred to as “water fleas,” are small planktonic crustaceans. They are a nutritious and natural food source for many fish species, including freshwater and marine varieties. Daphnia can be collected from natural bodies of water or cultured for use as live or frozen fish food.
• Bloodworms (Chironomidae): Bloodworms are the larvae of certain types of midges. They are often available as frozen or freeze-dried fish food and are highly attractive to many fish due to their red coloration and high protein content.
• Tubifex Worms: Tubifex worms are small, reddish aquatic worms found in the sediments of freshwater habitats. They are a popular live or frozen food choice for many aquarium fish. However, it’s important to ensure that tubifex worms are from reputable sources to prevent the transmission of diseases to fish.
• Blackworms (Lumbriculus variegatus): Blackworms are freshwater annelids that are used as live or frozen fish food. They are a good source of protein and are often fed to fish that enjoy hunting for live prey.
• Mysis Shrimp: Mysis shrimp are small shrimp-like crustaceans found in both freshwater and marine environments. They are commonly used as frozen or freeze-dried fish food and are particularly popular in marine aquariums.
• Insect Larvae: Some fish, especially carnivorous and insectivorous species, enjoy a diet that includes insect larvae. This can include various types of fly larvae, mosquito larvae, and other aquatic insects.
• Snails: In some cases, certain fish species will consume small snails as part of their diet. This is more common in species like pufferfish and some loaches.
• Copepods: Copepods are small crustaceans found in both marine and freshwater ecosystems. They are a valuable live food source for many marine and some freshwater fish, particularly marine reef species.

This food element develops over time in most aquariums.  However, if your occupants require this food element right away most pet stores can accommodate your requirements.  If needed check online for suppliers of invertebrates.  It is recommended that the aquarist consider non-living invertebrates initially, or at least until the aquarium begins supporting invertebrates on its’ own.

Biofilm, Protozoa, insect larvae: Biofilm, protozoa, and insect larvae are natural food sources that can be valuable components of the diet for many fish species, both in their natural habitats and in aquariums. These organisms offer a diverse range of nutrients and are often sought after by fish for their high protein content and palatability.

1. Biofilm:

• What is Biofilm: Biofilm is a complex, slimy, and naturally occurring community of microorganisms that forms on various surfaces in aquatic environments, such as rocks, substrate, and plants. It consists of bacteria, algae, fungi, and other microorganisms.
• Fish Diet: Many fish species, particularly herbivores and some omnivores, graze on biofilm as part of their natural diet. Biofilm can provide a source of protein, carbohydrates, and other essential nutrients for these fish.
• Use in Aquariums: In aquariums, biofilm can develop naturally on surfaces like rocks and driftwood. Some aquarists intentionally encourage biofilm growth by allowing surfaces to develop it, providing a supplemental food source for their fish.

2. Protozoa:

• What are Protozoa: Protozoa are single-celled microorganisms that are abundant in aquatic environments. They come in various shapes and sizes and are a diverse group of microorganisms.
• Fish Diet: Many fish, including small fry and some filter-feeding species, consume protozoa as a primary or supplemental food source. Protozoa are rich in protein and can be an essential part of the diet for some fish.
• Use in Aquariums: In aquariums, live protozoa cultures can be fed to fish, especially small or fry-stage fish that benefit from tiny food particles. Culturing protozoa at home is possible and can provide a steady supply of live food.

3. Insect Larvae:

• What are Insect Larvae: Insect larvae are the immature stages of insects, such as flies, mosquitoes, and beetles. They come in various forms and sizes, depending on the species.
• Fish Diet: Insect larvae are a highly sought-after natural food source for many fish species. They are rich in protein and essential nutrients. Fish that feed on the water’s surface or near the bottom often consume insect larvae.
• Use in Aquariums: Insect larvae can be offered to aquarium fish as live, frozen, or freeze-dried food. Drosophila (fruit fly) larvae, mosquito larvae, and blackworms are examples of insect larvae used as fish food. Some aquarists also culture their own insect larvae as a sustainable food source for their fish.

In the aquarium biome, compatibility is largely comprised of four areas.  They are: Food types, Water chemistry, Species behavior, and Environmental.   The closer there is alignment in these areas and their sub-elements, the greater the compatibility potential.  Many aquatic occupants will overlap in these areas, or not be specific to a particular element in an area.