There is lots of science on Discus nutritional needs and even gut microbes. Here is but on example.
Zhang, Y., Wen, B., Meng, L.J., Gao, J.Z. and Chen, Z.Z., 2021. Dynamic changes of gut microbiota of discus fish (Symphysodon haraldi) at different feeding stages.
Aquaculture,
531, p.735912.
Abstract
Discus fish (
Symphysodon haraldi) is an important
ornamental fish. Owing to its unique parental care behavior, there are generally four feeding stages from fry to adult. Gut microbiota plays an important role in fish nutrition metabolism. Different food resources may potentially affect the structure and function of host intestinal microbiota. However, studies on the response of discus intestinal microbiota during feeding changes are scarce at present. Here, we determined the succession of gut microbiota of discus that were subjected to abrupt and extreme diet changes, from parental skin-mucus,
Artemia nauplii,
Chironomidae larvae to beef-heart
hamburger, a total of four feeding stages. As diets changed, the community diversity and richness of discus intestinal microbiota first decreased, then increased, and finally decreased. Content of
Firmicutes in the gut of discus gradually increased, while the level of
Chloroflexi gradually decreased. The levels of
Fusobacteria and
Verrucomicrobia increased and then decreased, while the contents of Proteobacteria and
Actinobacteria decreased and then increased. Gut
bacterial community of discus feeding parental skin-mucus was significantly different from other three feeding stages. Moreover, at the stage of feeding parental skin-mucus, the predicted pathways of RNA processing and modification and extracellular structures were more enriched than those at other feeding stages. However, at the stage of feeding beef-heart
hamburger, the pathways related to nutrients transport and metabolism and energy production and conversion were more enriched than those at other stages. Changes in discus intestinal microbiota might suggest their potential in adapting to different food resources.
Introduction
Discus fish (
Symphysodon haraldi) is a domesticated ornamental species and has been regarded as King of Aquarium Fishes for its disc-shaped body and bright colors (Livengood et al., 2009). Through a long-term domesticated process, natural pairing, spawning, fertilization, and hatching, the culture of discus fish has been realized in aquatic tanks (Chellappa et al., 2005; Satoh et al., 2018). Discus fish has a unique parental care behavior that
newly hatched fry feed on parental skin-mucus (Buckley et al., 2010). The analysis of mucus composition shows that, similar to mammals, parents provide high quantity of nutritional and non-nutritional factors for offspring, including antibodies, essential ions, and hormones (Buckley et al., 2010). With the growth of discus,
the fry begin to feed on Artemia nauplii. As they grow up, the
juveniles begin to feed on Chironomidae larvae (Chong et al., 2002). When entering
the adult stage, the discus mainly feed on beef-heart hamburger (Chong et al., 2002; Song et al., 2016; Wen et al., 2018). Therefore, discus fish experiences four diet stages, from fry to adult fish.
from
https/www.sciencedirect.com/science/article/abs/pii/S0044848620319724?via=ihub
(
Underlining above added by me)