Koi -vs- Goldfish -vs- Minnows/Mosquitofish


When considering the best balancing of your pond, one should be aware of the mass (weight) of the fish involved and their symbiotic* relationship within ecosystem of your pond; the nitrogen cycle (refer to blog); more fish mass = more need for proper Biological filtration (refer to blog) and/or resulting plant growth. Remember that algae is a plant and thus if your fish load is heavy then there is more likely for your water-garden to experience a heavy algae “BOOM” growth -aka-“Going Green” (refer to blog).


For example, even a single large koi could off-set your pond balance and the result may be an unhealthy load on the pond, ….and a heavy algae growth as a result.

The Load effect based on weight of fish is as follows;

One adult mature Koi                     =        at least 60-70 goldfish  or                    =        more than 120 -140 minnows !! 


Another problem with Koi is that they can be voracious** eaters, eating up all the beneficial plants such as Anacharis ( refer to blog post on Anacharis). A large heathy growth of Anacharis and other aquatic plants would help to balance and keep your Pond looking clear and beautiful (Balanced).


*sym·bi·o·sis /ˌsimbīˈōsəs,ˌsimbēˈōsəs/ noun BIOLOGY; interaction between two different organisms living in close physical association, typically to the advantage of both.

**vo·ra·cious /vəˈrāSHəs/ adjective; wanting or devouring great quantities of food. “he had a voracious appetite”