Improving oxygen transfer in a Recirculating Aquaculture System, to increase production and promote the sustainability of raising tilapia indoors.

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2020: $26,990.00
Projected End Date: 01/31/2022
Grant Recipient: Ripple Rock Fish Farms LLC
Region: North Central
State: Ohio
Project Coordinator:
Traci Bell
Ripple Rock Fish Farms LLC

Information Products


  • Animals: fish


  • Animal Production: aquaculture

    Proposal summary:

    With increased demand for locally grown seafood, small farmers in the North Central Region are improving methods to raise fish indoors using Recirculating Aquaculture Systems (RAS).  However, costs to support fish densities at profitable levels is challenging.

    The driving force behind any successful RAS is oxygen.  If oxygen levels can be maintained, then waste is neutralized aerobically, feed levels are maximized, fish densities are increased and higher growth rates are achieved.  The solution seems obvious … increase the oxygen levels in the water.  However, liquid oxygen, used by larger operations, is simply too costly to be implemented on a small farm.

    The partners on this project seek to improve oxygen transfer rates using cost-effective methods including:

    • Home Health Oxygen Concentrator
    • Venturi Injector, and
    • Oxygen Saturator

    This innovative research will broaden traditional RAS methods.  Typically, low pressure systems appropriately designed for small farms, cannot support aggressive oxygen transfer methods.  It’s no wonder that 90% of small scale fish farms fail in the first 5 years of operation. We seek to assist small farmers; stabilizing their presence in this potentially sustainable industry.  Without a doubt, recirculating aquaculture is ecologically sound and socially responsible. The challenge is to also make it economically viable.


    Project objectives from proposal:

    1. Document current oxygen demand and determine the required oxygen supply necessary to support increasing fish densities (lbs/gallon) by 25%, 50%, and 75% over current levels.
    2. Design a plan to install a Venturi Injector and Oxygen Saturator into the existing raceway, supported by a Home Health Oxygen Generator.
    3. Measure oxygen levels in the water as fish grow (and biomass increases); monitor and make adjustments, over a 3-6 month period.
    4. Expand research to demonstrate the innovation at two additional fish farms, raising similar species, but operating differing systems.
    5. Document results and educate other small, local aquaculture farmers, and aquaponics producers.
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.