You have a planted tank. Everything is going well. Then, you see it.
Tiny tufts of black, fuzzy hair growing on your driftwood and Anubias leaves.
Black Beard Algae (BBA).
You try to scrape it off. It won’t move. You try to poison it. It comes back.
You go to the shop and ask for help. The uncle hands you a silver fish with a black stripe. “Ikan Bandaraya Siam. Eat everything.”
Wait. Before you buy it, look closely.
Are you buying the legendary Siamese Algae Eater (SAE)? Or are you buying the aggressive imposter, the Flying Fox?
Here is how to tell the difference and why it matters.
1. The Job Description
Why do we want the Siamese Algae Eater (Crossocheilus oblongus)?
- The Superpower: It is widely considered the only fish that will eat Black Beard Algae (BBA) and Hair Algae.
- The Work Ethic: They are constant grazers. A group of 3 can clean a fuzzy piece of driftwood in a week.
The Flying Fox (Epalzeorhynchos kalopterus) looks almost identical, but:
- It stops eating algae when it grows up.
- It becomes territorial and attacks other fish.
- It eats fish food, not algae.
2. The “Decoder” Guide (How to Spot the Fake)
You cannot trust the label on the tank. You must look at the fish.
Check 1: The Stripe (The Easiest Tell)
- True SAE: The black horizontal stripe has jagged/zigzag edges. Crucially, the black stripe goes all the way to the end of the tail fin.
- False (Flying Fox): The black stripe is smooth/straight. The stripe stops at the base of the tail (it does not go onto the clear fin).
Check 2: The Whiskers
- True SAE: Has 1 pair of tiny whiskers (barbels).
- False: Has 2 pairs (usually easier to see).
Check 3: The Color
- True SAE: Boring silver/grey body.
- False: Often has a pretty gold/yellow stripe above the black line. (If it looks too pretty, it’s probably the fake one).
3. Care Requirements
If you manage to find the True SAE, they are fantastic fish, but they have quirks.
- They Jump: They are powerful jumpers. If you don’t have a lid, you will find them dried up on the floor (Ikan Kering style).
- Size: They grow surprisingly big—up to 6 inches (15cm). They are essentially mini-carp. They need at least a 3-foot tank when fully grown.
- Social Life: They are shoaling fish. Keep at least 3. If kept alone, they get shy. If kept in a pair, the stronger one might bully the weaker one.
4. The “Lazy” Phase
Here is the catch. SAE are great when they are young (2-3 inches).
As they get older and bigger, they realize that Fish Pellets taste better than Algae.
- The Trick: Don’t overfeed your tank. If the SAE is full of pellets, it won’t touch the algae. You have to keep them a little bit hungry to make them work.
The Bottom Line
If you are fighting Hair Algae or BBA, the True Siamese Algae Eater is your best biological weapon.
Just take a minute at the shop. Look at the tail.
- Stripe goes through the tail? Buy it.
- Stripe stops at the tail? Put it back.
