In the ornamental koi world, colour is money. A koi with deep, vibrant red patches commands a completely different price point than a dull one — even if the body structure is identical. Most commercial feeds solve this with synthetic astaxanthin. It works, but it’s expensive, and experienced breeders can usually tell the difference between chemically forced colour and naturally developed pigmentation.
The TATSUMI formulation takes a different approach. The same 2023–2024 university research trial conducted by UCSI University and Universiti Putra Malaysia that validated our BSF protein base also tested what happens when red dragon fruit peel is added to that foundation. The results answered two questions at once: does it actually improve redness, and does colour enhancement come at the cost of growth?
Why koi can’t colour themselves
Koi cannot produce their own pigments. Every shade of red, orange, and yellow on a koi’s body comes entirely from what they eat. In the wild, common carp source carotenoids from insects, algae, and organic matter in their environment. In a pond or tank, they get only what’s in the pellet.
Most commercial feeds use synthetic pigments to compensate. Red dragon fruit peel is a natural source of betacyanin — the same class of pigment compound responsible for the deep red colour in the fruit itself. When processed and incorporated into feed at the right level, it functions as a natural colour enhancer that the fish’s body can actually recognise and utilise.
What the research measured
Redness was tracked using a calibrated portable colour analyser measuring RGB values, with the same spot on each fish measured at Day 0 and Day 45. Photos were also taken under controlled lighting and analysed using Adobe Photoshop’s colour dropper tool, producing hex code comparisons of the exact skin patches before and after feeding.
The BSF plus dragon fruit peel group showed a statistically significant increase in redness intensity over 45 days. The commercial diet group showed no significant change. The basal fishmeal group showed no significant change either. Only the natural BSF and dragon fruit peel combination moved the needle on red pigmentation.
The tradeoff that didn’t happen
Here’s what’s normally expected: when you push a fish toward stronger pigmentation, growth tends to slow. The body diverts metabolic energy toward processing and depositing pigments, and growth rate suffers.
That didn’t happen here.
The BSF plus dragon fruit peel group achieved a weight gain of 12.53g over 45 days, compared to 7.96g on the commercial diet. SGR — daily growth rate as a percentage of body weight — came in at 1.04% versus 0.63% on commercial feed. The fish got redder and grew faster at the same time.
The economic data is equally direct. The profit index of the BSF plus dragon fruit formulation was 4.22. The commercial diet profit index was 1.15. Same fish, same feeding period — nearly four times the economic return per kilogram of koi raised.
What natural colour development actually looks like
The colour shift observed wasn’t the sudden, uniform flush you sometimes see with high-dose synthetic pigments. It was a progressive deepening of existing red patches — the kind of development that looks like the fish is expressing its genetics rather than being dyed. The Photoshop hex code comparisons in the research documentation showed distinct shifts toward deeper, more saturated reds across the test group, while the commercial feed group remained visually static over the same period.
For breeders preparing fish for competition or sale, that difference in visual quality is not cosmetic. It’s the difference between a fish that looks maintained and a fish that looks thriving.
What this means for TATSUMI
TATSUMI is built on this exact research foundation — BSF protein for growth and feed efficiency, with red dragon fruit peel for natural colour enhancement. The two work together rather than against each other, which is what makes the formulation different from conventional colour-enhancement feeds that sacrifice one performance metric for another.
If your current feed is producing slow growth, flat colour, or both, the data above explains why. And it points toward what to chang
