How We Grow

At PortFish, Ltd., we are committed to finding sustainable ways to produce food locally, year round.  We do this through a number of methods, but the common denominator is WATER:
maximizing its effectiveness, while minimizing usage.

  • Green House  The PortFish facility incorporates the use of a green house to extend the growing season in our cold, Wisconsin climate.
  • Aquaponics  When you put Aquaculture and Hydroponics together, you get Aquaponics – a closed loop system in which plants are grown in water that is also inhabited by fish (in this case, yellow perch).  The fish waste feeds the plants, and the plants clean the water for the fish.  While the fish can occasionally be harvested for food, the real output are the greens.
  • Hydroponics  Who needs soil?  Take the ecosystem out of Aquaponics and you’ve got Hydroponics.
  • Cold Frames  A cold frame is like a mini-greenhouse that can extend the growing season, as well as minimize water usage.

 Where It Started

 Special thanks to Dave, the Two-bit Guru for the video!

PortFish, Ltd. Model 3


In 2012, PortFish, Ltd.’s opened its 4,400 square foot Model 3 aquaponics facility in a former agricultural storage building that was part of what was once the Port Feed Grain business, located at 3781 County Road KW in Knellsville, Wisconsin. Knellsville is an unincorporated community on the north side of Port Washington, in the town of Port Washington.  We welcome visitors – contact us for a tour!

The former ag-storage building is a timber-frame structure measuring 28’ x 94’ and was in sad condition prior to being selected for the PortFish Model 3. The roof was more sponge than protective cover and the first thing that was done was the complete replacement with a new single-ply rubber membrane surface. Remarkably, the structure itself is in very sound condition and no rafters or other timbers required replacement. The configuration of this structure consists of seven 13’ x 28’ bins for ag-products.

perch production tanks

Currently, four of the seven bins have been completely remodeled and are used for the fish habitat, nitrification filter and plant propagation portions of the aquaponics activity. The floor plan at the bottom of the page identifies the location of the various activities. You will notice the 17.5’ x 96’ green house addition. This is a 35’ x 48’ FarmTek greenhouse kit that was modified to fit the needs of Model 3.


Please visit our Facebook page to see the latest progress photos!


Want to lend a hand?  Contact Us to volunteer or click here to send a donation!
PortFish Ltd is a 501(c)(3) non-profit organization.  Your donations are tax deductible.

Contact Pat Wilborn for information.

Click on the image below to see our floor plan.

PortFish Aquaponics Floor plan



The PortFish Model 2

Exterior View

In August 2009 in an attempt to maintain control and reduce costs, we built a two-level addition to our house. The upper level is where the plants are grown in a media-based aquaponics system. Because it gets cold in the winter, this space is heated via a heat exchanger connected to the house’s heating system. On the other hand, it is not unusual for the summer time heat in this space to go past 90°.

The lower level is where the yellow perch are maintained. The fish require 72° water and the water return system is designed to drop the summertime temperatures back to 72-76°. Model 2 has provided us with an understanding of what is needed to maintain the quality of life for the fish, while also getting plants like basil, lettuces, tomatoes, watercress, herbs and some house plants like philodendron, papyrus, and helxine soleirolia, to grow year-round. The key to a successful plant system is to regularly harvest – the plants just keep growing – it’s amazing!

How the PortFish Aquaponics Model Works

Perch Tank

Lower Level of a two-level plant bed

The system consists of a 300-gallon stock tank (Fleet Farm) on the lower level. We maintain a density of 150 to 200 fish (6 to 10-inches). A higher density is possible, but it is harder to maintain the water quality. As well, at 150 fish we are creating more nutrients that our two 4’x 8’ plant beds require – a successful and sustainable system must be balanced, e.g., Model 3.

Water flows from the fish tank into an adjacent sump tank through an overflow standpipe located at the center of the tank. From there, a pond pump moves water up to the two elevated plant trays in the solarium on the upper level, about a 12-foot rise.

When the nutrient-rich fish water arrives at the upper plant tray, gravity takes over, i.e., the water flows across the top tray and is directed to the lower tray, where it crosses over and returns back to the water-cooling reservoirs and eventually back to the fish tank.

Sounds simple, but what makes it so special is that given a single input of fish feed, the plants receive the nutrients needed for growth and in the process, the quality of the fish habitat is maintained. That is, nutrients in the water are taken up by the plants and in the process the water is cleansed. No mention of the participation of bacteria in this process is given, but this is the part in which an aquaponics system mimics nature, and makes for a sustainable system.

The PortFish Model 1

Behind the Scenes

Our original Model 1 aquaponics system confirmed that fish and plants could coexist in a symbiotic relationship. There was a learning curve for caring for the fish (fish must be feed-trained), and learning which plants would do well is a given system based on the quantity of lights and nutrient content of the water. It wasn’t until we built Model 2 that we learned about the importance of bacteria to these systems.

Nitrosomonas and nitrobacter bacteria are responsible for converting fish waste to the required plant nutrients. Nitrosomonas consume the ammonia created by the fish and convert it to nitrites. The nitrobacter consume the nitrites and convert them it to nitrates, which are absorbed by the plants. In this process, the water is cleansed, the water quality for the fish is maintained and the system accomplishes a state of equilibrium.

Comments are closed.