American Flagfish - Care Guide for Algae Eater

They’re visually stunning (both in color and body shape), peaceful, and easy to care for. This makes getting on a no-brainer for anyone looking to switching things up a bit! In this guide, we’ll cover everything you need to know about rope fish care. Info like tank mates, diet, lifespan, and size are all in here!

Overview

The American Flagfish is an undemanding Killifish that is highly sought after for its algae-managing services. If that is not reason enough to acquire this hardy and interesting New World Killifish, the unique marking and color pattern is sure to win you over. It is not difficult to see why this Killifish is named after the American flag. Alternating horizontal stripes of red and creamy green stretch across the body and iridescent scales sparkle like stars on the blue anterior of the American Flagfish. This wonderful piscine Star-Spangled Banner is sure to capture the imagination of hobbyists and onlookers alike.

The American Flagfish fish originates from still and slow-moving marshes, swamps, lakes, and ponds from Florida south to the Yucatan Peninsula. Provided with proper water quality, the American Flagfish can adapt to a variety of water conditions. The American Flagfish is a great addition to community aquariums, planted aquariums, cool-water aquariums, or even small outdoor ponds. The ideal aquarium environment for the American Flagfish should include driftwood, roots, and rocks for ample hiding places. Dense planting along the sides and rear of the aquarium and finish with a cover of floating plants. Be sure to leave an open swimming area in the center of the aquarium. To help bring out the best coloration in the American Flagfish, consider using dark substrate. The female American Flagfish is larger, more full bodied, and tends to be more yellow in coloration than the male. The dorsal fin of the male American Flagfish will tend to be more ornate and the body is more olive-green in coloration.

The American Flagfish will accept most live foods such as brine shrimp, white worms, tubifex, and some commercially prepared flake and frozen foods. If sufficient algae is not present in the aquarium, supplement the diet of the American Flagfish with prepared algae flake food or algae tablets.

Jordanella floridae is a 2- to 2.5-inch (5–6 cm) North American pupfish, or type of killifish. It is not an annual killifish, meaning that it lives longer than one year and does not need to be immediately bred to maintain the population. Its common name comes from the male’s unique coloration — rows of red and blue horizontal striping with a yellow shoulder patch — that looks like the stars and stripes of the United States flag. The female, on the other hand, is smaller, less colorful, and has a rounder abdomen when carrying eggs. Both sexes display a prominent black spot on the sides of their bodies, but females often have another small black dot on the back edge of the dorsal fin. Personality-wise, they are very active and constantly dart around looking for algae and other leftover crumbs to eat. Their mouths are perfectly shaped for ripping off hair algae, black beard algae, and other fuzzy types of algae.

How to make an aquarium for American Flagfish 

In the wild, they come from swampy Floridian marshes that are full of vegetation and consist of harder water or mildly brackish water. However, they are extremely hardy and can handle a wide range of parameters from pH of 6.5–8.5, soft to hard water, and 64–86°F (18–30°C). As a North America species, flagfish can thrive in unheated aquariums that have a tight-fitting lid to prevent escape. Some people put them in outdoor mini ponds during the summer to help eat algae and mosquito larvae.

Are flagfish schooling fish? Similar to dwarf cichlids, males can be quite territorial towards one another, whereas females tend to be more docile. Therefore, we recommend getting a ratio of one male for every two to three females. A pair of flagfish can live in a 20-gallon aquarium, but you should increase the tank size for each additional male so that they can each establish their own space.

Are flagfish safe with aquarium plants? To reduce fighting among the fish, we usually recommend getting lots of live aquatic plants to help block line of sight. However, in their eagerness to eat algae, flagfish can sometimes accidentally tear up more delicate plant leaves. We’ve had good luck putting them with tougher plants like java fern, fast-growing plants, and java moss for breeding purposes. Some hobbyists recommend keeping them well-fed to minimize any nibbling on leaves.

What fish can live with flagfish? Because of their feisty personalities, we recommend keeping them with other fast-swimming, boisterous tank mates that are similar in size. Zebra danios, corydoras catfish, loaches, and livebearers have all gotten along well with our flagfish. However, they are likely to predate on dwarf shrimp like cherry shrimp and ghost shrimp.

Diet & Feeding

Omnivorous. Will accept most meaty foods and also requires plenty of vegetable (particularly algae) content. 

American Flagfish predominantly graze on available algae in the aquarium. However, if the algae supply is insufficient, supplement their diet with high-quality dried foods such as flakes, pellets, or algae wafers, as well as live and frozen options such as brine shrimp, white worms, tubifex, daphnia, and bloodworms. Additionally, providing them with occasional treats of blanched vegetables like zucchini or spinach would be beneficial to their nutrition. A well-rounded diet is critical to promoting their overall health and vitality, and aquarists should take care to provide a balanced selection of foods to ensure their American Flagfish thrive in the aquarium.

Flagfish are not too difficult to breed and tend to spawn during the spring and summer seasons when the water is warmer. Mating behavior consists of nipping and chasing until the pair embrace and the female releases her eggs over the course of several days. Provide DIY spawning mops, java moss, and other dense foliage to serve as spawning sites and extra cover to hide the newborns.

Some biologists have reported that the male exhibits parental care by chasing away intruders from the spawning site, fanning the eggs to increase water flow and oxygenation, and eating any eggs that become infected with fungus. However, breeders often remove the eggs into a separate hatching bin to increase the yield and prevent predation. Depending on the water temperature, the eggs may hatch within a week or two. Once the newborns are free-swimming, feed them several small meals each day consisting of live vinegar eels and powdered fry food until they’re big enough to eat live baby brine shrimp and micro worms.

The Florida flagfish is such a gorgeous and useful species that everyone should try out at least once. If you’re looking for a whole team of different algae eaters to help you clean up your planted aquarium, read our article on the 10 Best Algae Eaters for Freshwater Aquariums.