Bitterling – Assorted
Bitterlings are carp-like in appearance and are a great addition to either a backyard pond or aquarium. Their bodies are generally silver to gold in color, and their dorsal and anal fins are highlighted in white. When mature, they will develop either a pink or blue hue at the base of their caudal fin.
The ideal aquarium size is at least 30 gallons, with plenty of plants (either real or plastic), rocks providing hiding places, and a substrate of gravel or sand.
Bitterlings are popular in ponds with large koi, as they feed on parasites such as anchor worms. They are active fish that also consume insect larvae and help control mosquito populations in water gardens.
| Feature | Detail |
|---|---|
| Size | At least 30 gallons |
| Color | Silver to gold body, white-finned, pink or blue base on caudal fin when mature |
| Substrate | Gravel or sand |
| Plant Requirement | Plants (real or plastic) and hiding structures like rocks |
| Feeding Habits | Parasites (e.g., anchor worms), insect larvae, mosquito larvae |
FAQ
What is the ideal tank size for bitterlings?
The ideal aquarium size for bitterlings is at least 30 gallons.
Do bitterlings help control pests in a pond?
Yes, bitterlings feed on insect larvae and parasites such as anchor worms, helping to control mosquito populations and other pests in water gardens.
What color do bitterlings develop when mature?
When mature, bitterlings develop either a pink or blue hue at the base of their caudal fin.

Gavin Abraham –
Bitterlings have been a great addition to our koi pond. They actively feed on anchor worms and mosquito larvae, which has reduced parasite issues in the pond. The fish are active and colorful, especially when they mature with the pink or blue base on their tail.
Michael Hardacre –
We added bitterlings to our 40-gallon pond and noticed a significant drop in insect larvae. They seem to enjoy the plants and rocks, and they stay active throughout the day. The color change in their fins after a few months was noticeable.
Anne Cameron –
The fish are easy to care for and have become a natural part of our pond ecosystem. They help keep the koi healthy by eating parasites. The silver to gold body with white fins is very attractive, and the mature coloration is a nice touch.