Aquarium & Tropical Fish Site

Jordanella floridae
American Flagfish, Flag Fish

 Age of Aquariums > Freshwater Fish > American Flagfish - Jordanella floridae

Photos & Comments

Jordanella_floridae_1.jpg (16kb)
Photo Credit: Susankatomerit

Name: Jordanella floridae
Origin: Mexico to Florida

Size Tank pH Temp
6 cm 40 L 7.5 24C


Jordanella floridae is one of the oddballs among killifish. The body shape of a male is very distinctive and instantly seperates it from all other killies. The female is a bit similar in shape to Cyprinodon (pupfishes) which they are said to have some affinities to. The first ray of the dorsal fin is hard like those present in the spinal dorsal of cichlids, another unique trait.

This fish's pattern is very hard to describe, so please bear with me as I try. The color pattern of the male is quite distinctive. On his squared off body he has rows of red horizontal stripes. His back and in front of the dorsal fin is green, or in some cases blueish. A black spot is present on the side of most males, though it may be faded out in some cases. Below the spot many specimens sport yellow between the red horizontal stripes. This usually bleeds to white away from this area, but in some cases the whole side may be golden. Also present are faint vertical bands, which can be shown in varying degrees of intensity. None of these patterns have clear marked off boundaries and bleed together. The fins have red spots in them arranged to form horizontal rows. The tail is usually clear. The complete effect, if you take the green front as the field of stars is something that does resemble the pattern on the American Flag.

The female looks quite different from her mate. She is less squared off and does not show most of the male's color pattern. She is a peachy, tan, or cream color and has the same brown bands as the male, only much more intense. The middle of each band appears to have been pushed forward...which may make it look like a checkerboard pattern. On her side she has a large black spot, ringed with white. This pattern is quite attractive and in some occasions I consider the female just as attractive as the male.

These fish, as you might expect, are quite variable. They can change color and pattern when startled to a dull brown with the bands more intense to help blend in with the bottom. Males also vary with the amount of each trait shown. In some males, for example, the "field of stars" is almost absent.

Jordanella floridae is a hardy fish and does not ask much of its keeper. While they will do fine in tanks as small as 10 L for a single happy pair, in the case of a breeding setup larger tanks are better for display. One hobbyist reported that he found that the fish grew slower in a 40 L than a 350 L. They can be shy at times, but providing some plants to retreat to and more intense light should encourage them to show themselves more. They are quite tolerant of cold (10C is tolerated), but like the temperatures warm. 27C isn't too warm for them. They do best if kept by themselves or with fish of similar size. Tankmates should be either fast or able to defend themselves

American flag fish are quite interesting to watch. They tend to hug the bottom or otherwise stay close to the plants. They will graze on many kinds of algae, but may occasionally nip other plants. Usually the damage is minimal though. Male and female pairs tend to stay close together and occasionally nip at or nuzzle one another. It is best to keep only one male, unless you have a spacious tank, as they will fight. Sometimes extra females may not be safe. I originally started with a trio, but before long the smallest female dissappeared. If you want to keep the flagfish strictly for algae eating, some advise you to keep only females. I have not tried this, but I think they are on the right track.

Jordanella floridae is an omnivore and not picky about types of food. They will eat just about anything: worms, shrimp, flakefood, etc. are all taken. They do have a requirement for vegetable matter, so boiled spinach or halved peas should be offered. Peas are a particular favorite for my fish. I would be careful with rich foods like worms and make sure the fish get adequate amounts of vegetable matter.

Jordanella floridae is not very difficult to spawn. Mine lay eggs in both plants and on artificial spawning mops, but a few others claim they will fan out pits and guard eggs like cichlids. I have noticed my male will get more aggressive after spawning, but he doesn't appear to offer any care for the eggs. Then again, I have not been observing them carefully! I spawned mine in a critter keeper with around 8 cm of water and lots of plants or a spawning mop. Kept outdoors in a sunny place and fed on a varied diet which included a good amount of redworms, the fish soon spawned. It appears warmth and light help trigger spawning. Spawning is done in the typical killifish fashion. After displaying to the female the female will swim off to some plants with the male following. When she stops, the male will squeeze in next to her from below and then wrap his unpaired fins around her. Both fish quiver briefly and then with a jerking motion the egg is released. The fish part and before long find yet another spot to lay another egg. The eggs are adhesive and seem to have a sticky thread on them. Best left where they are and the spawning mop or plants moved to another container. When nearing hatching the eggs "eye up" (the fry, and its eyes, can be seen in the egg). An amusing note on Jordanella eggs is that sometimes the striped pattern of the fry will show through the egg.

The fry hatch in about a week and cannot swim very well...instead they dart along on the bottom looking like little shrimp. In a tank with substrate like sand they are almost impossible to spot. Feed microworms and baby brine shrimp. Since they cannot swim up into the water column easily shallow water to concentrate the food is best; some say it is a necessity. After several weeks the fry take on a more fishlike shape and can the swim up into the water column to feed. They grow quickly and from this point on pose little problems to raise. At a certain point all fish develop the distinctive spot on the back of the dorsal that is present on adult females. However, it will be lost in the males as they grow...but does not fade completely until the males are almost fully grown.

These fish are usually peaceful, but can also be incredibly aggressive. I've observed killings take place amongst juveniles which I suspect have something to do with mate selection sort of like cichlids. Juveniles are apparently very persistent, as little pinto bean sized fish can apparently find each other and get rid of rivals in my heavily planted 170 L bowfront! If you have single pairs things are usually fine and dandy, but I've noticed extra females are often killed...but whether by the other female or the male they both are after I'm not sure. Therefore if you are keeping a batch you may want to watch carefully and separate forming pairs accordingly.

Contributed by Joseph S.

I got a few of these to see if they could help with my hair algae problem in my 113 L molly and platy tank. I had 4 SAE in it, but they weren't doing much for my hair algae problem. I was ready to tear down the tank and start over, till my buddy told me to try the Flag fish. He gave me five and I put in my tank, but didn't expect much. A few days later I was walking by the tank and my son told me that we now had orange hair algae too. I looked in the tank and sure hair algae floating around. I didn't know what it was and did a search for orange hair algae and got nothing. I looked in the tank to see where it was growing, and to my surprise, it was the waste product from the flag fish eating orange fish food and the green hair algae. It was coming out like intact(long 3-4 cm pieces) and orange. What great little algae eaters. Since then I've seen them grab long hair algae, shake their heads to get it free and eat it like noodles. What great fish.

Contributed by a visitor

I was suprised how territorial these fish could be. I added a male and female to my 500 L tank, which contains shoals of tetras, corys and rams. Within a week I had lost all my male rams (the females are fine but lonely). A pugnacious male fish. If you have dwarf cichlids then think very hard before you add a pair of these. I would say no.

Contributed by Mark Alleman

Wow, the flagfish is incredible. The male is more brightly colored than the females, but both are beautiful fish that have good personality. Even more amazing is the way these little guys eat hair algae. They resemble bulldogs, thrashing their heads, tearing and ripping it off plants while doing no harm to the forage. I placed my 3 beauties in the tank, and in less than 5 minutes, they were already disposing of my hair algae menace. Beautiful fish, that keep plants algae free!

Contributed by Matthew

Not a community fish! I bought three males and returned them after three days! They settled in nicely and went to town on the algae in my 100 liter tank. However, they aggressively pursued my three panda corys and my two guppies, tearing chunks out of their fins, and also were attacking my other plants that I did not want destroyed. They did not bother my scissor tail rasboras, thread fin rainbow, lemon tetras, dwarf puffer, and von rio tetra. They also ignored my shrimp. I was so disappointed to have to return them for the safety of my other fish, as I thought they were very entertaining and beautiful. The fish store manager did not believe me as he never had a problem with them himself. A single Flag Fish might have been better, or perhaps a female, but I'm not sure I want to risk putting them in my tank again.

Contributed by Judy F

A friend of mine advised me to get one of these after I started to get black hair algae, and I was amazed when after just a few days it had really gone to town on the stuff. It was in my tank with about 15 zebra danios, 2 large angels, a panda cory, a female siamese fighter and a golden panchax killifish, and I had no problems keeping them together.

Contributed by Chris

I now have a tank entirely devoted to one particularly troublesome male flag fish who refuses live peacefully with any other fish. We are currently nursing those were not mercilessly killed but merely stressed and damaged. I think he may be just a rotten individual as I have heard good things about this fish and for the first month we had him he was absolutely fine.

Contributed by Charlie Harris

I recently bought 4 FFF to work on some hair algae in my 470 L tank. I was worried because I have quite a few other fish, and was told the FFF can be aggressive. Mine are just the opposite! I hardly ever see them since they spend all of their time hiding in the plants. I am not sure if mine are just playing shy or this really is a great fish. It is fun to play hide and seek to watch them.

Contributed by Tessa

I've read terrible things about FFF (Jordanella) being fin nippers and fish murderers, but my experience with them over the years has been the opposite. I guess they can go either way. Mine have always been shy, keep to themselves, and are fixated on eating algae, even the dreaded black brush kind which they tear off in mouthfuls. They also hang out at the top of the tanks, not the bottom or middle, maybe because there is more algae nearer to the lights. Right now I have a pair (I don't know what sex) in my 200 L with 2 mature angels, 3 roseline sharks, some rummy nose tetras, shrimp, and a few catfish with no problems. However I have had the experience of adding another FFF to a tank that had only one, only to lose one within a few days of unknown cause (I never saw them fighting but who knows). If you have algae, they are well worth trying out.

Contributed by Donna

Got some experience to share for this page? No registration necessary to contribute! Your privacy is respected: your e-mail is published only if you wish so. All submissions are reviewed before addition. Write based on your personal experiences, with no abbreviations, no chat lingo, and using proper punctuation and capitalization. Ready? Then send your comments!

oF <=> oC in <=> cm G <=> L