Two identical coupled warmwater ebb-and-flood gravel aquaponic systems (unit I, unit II) without additional biofilter were evaluated for the effect of fish species choice onto culinary herbs (basil - Ocimum basilicum, parsley - Petroselinum crispum and marjoram - Origanum majorana) and resulting water parameters. The daily feed input increased over the experiment (70–450g, total 70days), resulting in an maximum feed input of 150gd−1, or 25% less than during an earlier study under the presence of a 60L trickling biofilter. Using dissolved oxygen to indicate system performance, the experiment had a run in phase, exponential phase, and accumulation phase. Lowest dissolved oxygen (DO) concentrations were measured inside the hydroponic units, with no general differences in chemo-physical parameters between each separate plant box. Nile tilapia red strain fingerlings (Oreochromis niloticus; initial weight 3.32g±1.63) were stocked in aquaponic unit I and African catfish fingerlings (Clarias gariepinus; initial weight 3.92g±1.63) in unit II. Due to the high feed input at the beginning of the experiments, specific growth rate and feed conversion ratio were very good, and significantly better for C. gariepinus (3.30%d−1±0.02, 0.61±0.01) compared with O. niloticus (2.81%d−1±0.12, 0.91±0.08). Feed conversion corresponded with much younger fish with effective feeding under restricted food input. The oxygen consumption was lower for C. gariepinus with a difference of 8.34% to O. niloticus. Due to reduced natural light illumination and water temperature (winter season), plant growth was generally reduced but two times better in the O. niloticus stocked unit (0.30g±0.37 in basil, 0.55g±0.39 in parsley) compared with C. gariepinus (0.12g±0.21 in basil, 0.27g±0.31 in parsley). A newly calculated aquaponic growth factor (AGF) illustrates the opposite fish and plant yields for both fish species.Statement of relevance: The influence of different fish species on plant growth has been examined only rarely in aquaponics. We hereby describe the influence of different types of fish on physical parameters and plant growth in coupled aquaponic systems for diversification.