Page Loading

Return To Article List

Fishmonger Newsletter

Rainbowfish Article, & Construction Updates

February, 2022

Logo

Fish Store Construction Progress

Tons of progress this month! The water treatment equipment has been placed and a lot of it has been plumbed in. The surface well and return for our water source is about halfway built. We have lights wired in…much easier to see! The construction of the aquarium racks has begun. I don’t want to jinx anything, but I think we should be done construction by March 1st…fingers are crossed and libations to the fish gods have been made.

Almost DONE New Fish Store BUILD

The “big boy” carbon filters have been plumbed in and the backflush cleaning valves are installed. The filtered water is plumbed to the economizer (heat exchanger).

The UV filters are plumbed in. Next step is plumbing in the blue boilers on the left.

Here’s a jig fixture we built to aid us in the construction of our aquarium racks. With this thing, we are able to whip racks together quickly and accurately…and we don’t have to crawl around on the floor!

Here is the resulting pile of racks.

First rack is on its feet! Most of the spacers are still missing, but I just HAD to take a pic as soon as it was free standing.

Lots more racks coming together.

Spacers have been added to the aquarium racks. We have some stiffeners yet to add to keep the racks in square once they have been placed in their permanent locations.

Work on the surface well for our water source is coming along.

Perforated feeder pipes on the right side of the well have been placed and covered with a few feet of gravel.

The main cistern has been placed and plumbed in.

Working on the feeder pipes on the left side of the well.

All the feeder pipes and the cisterns have been installed and plumbed. Now we need to plumb from the cistern to the building and build the return for the water leaving the building.

Featured Article

A New Color in the Rainbow: Melanotaenia sp. “Kali Tawa”

Article & Photos by Ryan Reamy

Edited by Dan Hodnett

Seemingly overnight, the Melanotaenia sp. “Kali Tawa” became the most sought-after rainbowfish in the hobby. With a shimmering blue body and a bold red tail, it’s no surprise that Gary Lange affectionately dubbed them “The Most Amazing Rainbowfish”. Not only do the males show consistent color throughout the day, they take on even more breathtaking colorations when sparring and spawning.

The fins of Melanotaenia sp. “Kali Tawa” turn blazing white when they display.

This undescribed species of rainbowfish was collected in the summer of 2019 near Lengguru in West Papua by Gary Lange, Johannes Graf and Wim Heemskerk. Gary had mentioned that the Tawa were collected in karst spring water that measured at 24.3c, with a GH of 12, conductivity of 330uS, and a pH of 7. Most rainbowfish are highly adaptable and this species is no exception. Where some Tawa breeders in the United States have very hard mineral rich water, I have virtually no hardness or minerals in my water. I’ve found them to be a hardy and spunky little fish that can even hold their own against some larger rainbow species. Interestingly, they were found alongside two other larger Melanotaenia species: Melanotaenia sp Lengguru and Melanotaenia sp Lobo that should also be entering the hobby in greater quantities soon.

The blue body, white fins, and bright red tail make Kali Tawa a stunning beauty.

Based off their sheer beauty alone, it wouldn’t shock me if they eventually became one of the most popular and widespread rainbowfish in the world. Even the colors they show when at rest are beautiful. Males of this species sport a rich turquoise blue body lined with copper stripes, a black vertical ink mark and a distinctive red tail. Many rainbowfish species turn their colors on and off based on their moods. Because of this, I find it difficult to share my love of rainbowfish with others when they come over and see a grey fish. I usually have to give them the cliché remark of, “Oh they look better in the morning” or “They usually look better than this, they aren’t looking their best right now…”. But fortunately, this little bow looks stunning all day long. This is a "dwarf" species which is said to top out at about 3 inches when fully grown. My breeders range from 2 to 2.5 inches at 2 years old. They thrive in planted tanks and a group can be kept in a 20 gallon aquarium...although I would recommend a 40-gallon breeder as a better tank size to give them a bit more swimming space. I wouldn’t consider this an aggressive fish, but males are quite boisterous when sparring and breeding. So, cover should be given to females to allow them to get away from males.

This is a “dwarf” rainbowfish, topping out at about 3”.

One of my favorite features about this species is the intense coloration that males can take on in different moods. When sparring against other males, they will turn their dorsal and anal fins bright white and will spread them as wide as they can.

The dark vertical stripe on the body helps distinguish this species.

When displaying for females, the color on their forehead intensifies. This is typical of many rainbowfish, but the Tawa take it to the next level. Visually, the blaze reminds me of molten lava pouring down the fish’s back. It really is one of the most intense breeding colorations I have seen from a rainbowfish.

Great shot of the blaze on full flash!

Although not as attractively colored as the males, female Kali Tawa have nice subtle orange striping and can show slight orange pigmentation to the tail. Females also sometimes spar amongst each other while showing some increased white highlighting to their dorsal and anal fins. Females can also show the distinctive vertical black ink mark on their side.

Even the females are nice looking.

When working with a newly collected species, you never really know what to expect as data is not yet available. I received 40 eggs from Gary Lange in April of 2020 and tirelessly researched how to hatch and raise rainbowfish eggs. I hatched and raised them at 82-84f degrees with small feedings 6 times a day of either 5-50 micron Golden Pearls, Sera Micron, infusoria or vinegar eels until they were big enough to eat live baby brine. They put on size fairly quickly and males showed color as soon as 4 months of age. I started noticing a few random deaths when the fry reached about 2 months old. I couldn’t identify any issues with parameters and oddly enough it seemed like the largest of the juveniles were perishing. I then realized that the temperature in tank had been reaching 86f in the daytime as we were nearing summer. After lowering the temp to 80f, I fortunately stopped losing fish. This leads me to believe they might be temperature sensitive in the higher ranges.

The juveniles I hatched from eggs reached sexual maturity fairly quickly and I started to breed them in good numbers. The only problem was the sex ratio. I had been raising fry at 80 to 82f with almost no issues but kept producing mainly females. Batch after batch resulted in almost a 1:10 male to female ratio. It turned out that I was not the only breeder in the United States that was experiencing this issue. Gary checked in to see if I was struggling with the same problem. After some discussion from other breeders in the US, it seems like this issue was occurring in a variety of water parameters. Since the skewed gender ratios were being noticed by breeders in a variety of water conditions, Gary advised that we should try cooler temps as he finally got a male to female ratio closer to 1:4 when he lowered the temp from 82f to 78f. This is when I learned that they were collected in water closer to 75f. I have since started breeding and raising Tawa in water closer to 75-78f. They can tolerate a wider range of temperatures, but I would recommend the mid-70s if you plan to breed this fish. Time will tell if my current batch of fry produces more males.

A breeding pair about to lay eggs in a spawning mop.

The popularity of this fish has certainly gone global. It seems Tawa were distributed more quickly and are more widely in Europe than in the United States. Interestingly, it also appears that European breeders are not facing the same skewed sex ratios that US breeders have. The spread of Tawa in Europe is thanks to Johannes and Wim, as they were able to get this stunning little bow in the hands of many hobbyists in the IRG (Internationale Gesellschaft für Regenbogenfische). This organization facilitated the spread of Tawa throughout Europe by allowing members to contact each other as they search for this fish. Throughout 2021, I successfully distributed this fish to several hobbyists around the country. Some hobbyists visiting Oahu, Hawaii have seen this species firsthand in local shops as I was able to get some fish over to a breeder in Honolulu in the fall of 2020.

This unique fish developed red spotting on the anal and 2nd dorsal fins.

One of the most exciting moments I’ve had while keeping this species is when I discovered a young male that showed a bit of a color mutation on his anal fin. The red spotting on this fish is mainly visible on the anal fin. But after putting him into a clear container, I can see the spotting also extends into the second dorsal fin. Although selective/line breeding is not really a mainstream segment of the rainbowfish hobby, I plan to try to selectively breed for more red spotting on the dorsal and anal fin in future generations. It will be interesting to see how the fry from this male will turn out.

A new generation being raised up.

Melanotaenia sp. Kali Tawa will always be one of the crown jewels of my collection. It’s one of those fish that can capture your attention from the other side of the room and draw you in closer. Whenever I walk by the tank, I find it hard not to pull out my camera to capture their beauty. I really hope more hobbyists get to enjoy this fish firsthand. Beauty may be subjective, but in my mind, this is the most beautiful rainbowfish ever to be introduced into the hobby.