When looking at food and diets we are often confronted with numerous ingredients with listed health benefits, it can be very confusing and difficult to understand. What adds to the complexity is the number of ingredients that can be added.

Like humans, fishes have nutritional requirements that’ll vary by species and even as the fish ages. These vitamins (Fig 2; Delbert, 2010) and minerals (Chanda et al., 2015) have various purposes.

This articles focus is not about catering for these vitamins and minerals particularly as a solid round diet; pellets, wafers and gel foods should cater for the basics of these. There is certainly an issue with many studies being species specific and focus on those used in aquaculture with a shorter term aim then ornamental fishes (Vucko et al., 2017). Previous studies have inferred that these aquaculture focused diets do fall short in terms of long term health (Žák et al., 2022), that is a whole other discussion.

Here our focus in those additional ingredients that might seem as strange but others are common herbs. This is not just about herbs or ingredients but what you could add to a gel diet.

I should quickly state that with a gel diet it’s quite easy to add ingredients that might make a diet cater better for a certain fish, gelling agent allowing. So for algivorous Loricariids I will add those extra algal powders to bulk out that element which meets their nutritional requirements (Vucko et al., 2017). It also would effect how long the product stores for once made into a gel so that should be considered.

Cellulose

This is a common additive due to the myth that Loricariids feed on wood, it has no nutritional or digestive benefit (Lujan et al., 2011). So of all the ingredients this is one I’d skip in regards to waste and feeding more.

Turmeric

This is a richly coloured member of the Zingiberaceae, Ginger family. It is described as being anti-inflammatory, antimicrobial etc. with many benefits for various organ systems but regardless of this it has limited availability for biological use as quickly removed from the system. This likely is influenced by how this root is added although being listed as hydrophobic and lipophobic makes uptake more difficult (Alagawany et al., 2021;

This is a richly coloured member of the Zingiberaceae, Ginger family. It is described as being anti-inflammatory, antimicrobial etc. with many benefits for various organ systems but regardless of this it has limited availability for biological use as quickly removed from the system. This likely is influenced by how this root is added although being listed as hydrophobic and lipophobic makes uptake more difficult (Alagawany et al., 2021; Fagnon et al., 2020).

One of the biggest concerns with adding in any additional elements to a diet is whether the product is toxic or not, luckily in terms of turmeric it is non-toxic although might have small effects on the gills. (de Moraes França Ferreira et al., 2017). Although there is a concern at higher volumes which depend on the individual species (Fagnon et al., 2020).

Basil

One of the herbs that is most easily accessable in so many different forms and even easy to grow. Much like expected basil is not just very palatable for fishes but also easily digested in an experiment on tilapia and sea bream. Benefits also included an improved growth rate (El-Dakar et al., 2008; El-Dakar et al., 2015). Most studies on this herb in regards to relevance as hobbyists seems to focus on their use aquaponically, as an ingredient is understandable for it’s lack of research and use as per a gram it’s not a cheap plant to use.

Paprika

For a better price and accessibility Paprika should be more of a popular ingredient as can easily be bought in bulk. The benefits of paprika are obvious given it contains many carotenoids (Maeda et al., 2021). These carotenoids are important for any red colourations in fishes (Hancz et al., 2003) with other health benefits (Amiruddin et al., 2021)

Seeds

Seeds are an interesting addition and certainly not for all fishes but there is evidence to suggest a diversity of aquarium fishes would feed on seeds in the wild (Weiss et al., 2016). One of these being Hypancistrus inspector (Armbruster, 2002). Although it is some what difficult to judge if these seeds are processed and to what extent. Due to seed dispersal by fishes it is highly likely that many seeds aren’t processed by a variety of fishes (Pollux, 2011) but those Hypancistrus do seem to be breaking them apart (Armbruster, 2002).

Rather then ingredients the aim is to give a starting point for further research. It might be worth exploring a wider range of ingredients and addition to a fishes diet. While there might not always be the research to back it up if it is safe then there is many benefits to the hobby by experimentation.

References:

Alagawany, M., Farag, M. R., Abdelnour, S. A., Dawood, M. A., Elnesr, S. S., & Dhama, K. (2021). Curcumin and its different forms: A review on fish nutrition. Aquaculture, 532, 736030.

H Amiruddin, M., Norhalis, M. F., Sumarwati, S., & Rashid, Y. N. (2021). Dietary effect of red paprika used to enhance the coloration of red tilapia (oreochromis niloticus). Journal of Aquaculture and Fish Health, 10(1), 25-33.

Armbruster, J. W. (2002). Hypancistrus inspector: a new species of suckermouth armored catfish (Loricariidae: Ancistrinae). Copeia, 2002(1), 86-92.

Chanda, S., Paul, B. N., Ghosh, K., & Giri, S. S. (2015). Dietary essentiality of trace minerals in aquaculture-A Review. Agricultural Reviews, 36(2), 100-112.

Delbert, M. G. I. (2010). Principles of fish nutrition. SRAC Publication, USA, 5003, 1-7.

El-Dakar, A., Hassanien, G., Gad, S., & Sakr, S. (2008). Use of dried basil leaves as a feeding attractant for hybrid tilapia, Oreochromis niloticus X Oreochromis aureus, fingerlings. Mediterranean Aquaculture Journal, 1(1), 35-44.

El-Dakar, A. Y., Shalaby, S. M., Nemetallah, B. R., Saleh, N. E., Sakr, E. M., & Toutou, M. M. (2015). Possibility of using basil (Ocimum basilicum) supplementation in gilthead sea bream (Sparus aurata) diet. Egyptian Journal of Aquatic Research (Online), 41(1).

Fagnon, M. S., Thorin, C., & Calvez, S. (2020). Meta‐analysis of dietary supplementation effect of turmeric and curcumin on growth performance in fish. Reviews in Aquaculture, 12(4), 2268-2283.

Hancz, C., Magyary, I., Molnar, T., Sato, S., Horn, P., & Taniguchi, N. (2003). Evaluation of color intensity enhanced by paprika as feed additive in goldfish and koi carp using computer‐assisted image analysis. Fisheries science, 69(6), 1158-1161.

Lujan, N. K., German, D. P., & Winemiller, K. O. (2011). Do wood‐grazing fishes partition their niche?: morphological and isotopic evidence for trophic segregation in Neotropical Loricariidae. Functional Ecology, 25(6), 1327-1338.

Maeda, H., Nishino, A., & Maoka, T. (2021). Biological activities of paprika carotenoids, capsanthin and capsorubin. Carotenoids: Biosynthetic and biofunctional approaches, 285-293.

de Moraes França Ferreira, P., Condessa, S. S., Rocha, J. S., Caldas, D. W., Gomes, J. R., Soares, M. T., … & Zuanon, J. A. S. (2017). Is the use of turmeric in the diet safe for fish?. Aquaculture Research, 48(9), 4623-4631.

Pollux, B. J. A. (2011). The experimental study of seed dispersal by fish (ichthyochory). Freshwater Biology, 56(2), 197-212.

Vucko, M. J., Cole, A. J., Moorhead, J. A., Pit, J., & de Nys, R. (2017). The freshwater macroalga Oedogonium intermedium can meet the nutritional requirements of the herbivorous fish Ancistrus cirrhosus. Algal research, 27, 21-31.

Weiss, B., Zuanon, J. A., & Piedade, M. T. (2016). Viability of seeds consumed by fishes in a lowland forest in the Brazilian Central Amazon. Tropical Conservation Science, 9(4), 1940082916676129.

Žák, J., Roy, K., Dyková, I., Mráz, J., & Reichard, M. (2022). Starter feed for carnivorous species as a practical replacement of bloodworms for a vertebrate model organism in ageing, the turquoise killifish Nothobranchius furzeri. Journal of Fish Biology, 100(4), 894-908.