Each year, the American Cichlid Association convention hosts fantastic speakers. The July 2024 edition in Cincinnati Ohio was no exception. In fact, I was able to snag an interview with one of the speakers who I had tried to get a few years prior (Dr. Ron Coleman). I also had the opportunity to talk to another speaker, Dr. Sam Borstein, who did an interview for the blog many years ago.
Dr. Borstein was a PhD student in 2015 when we did that first interview. I asked him at the convention if he wanted to do another and follow-up on his cichlid research journey and, thankfully, he agreed. Oh, and I would be remis if I didn’t point out that he did his undergraduate work with Dr. Coleman at Sacramento State University.
Dr. Borstein is now an Assistant Professor in the Department of Biology at Texas State University. Working with cichlids comes natural to him because he grew up in a home surrounded by fish. In fact, he became a master breeder with the Greater Chicago Cichlid Association (GCCA) before graduating from high school. Years ago, he also maintained a website (Sam Borstein’s Cichlids) where he profiled many of the cichlid species that he kept. Though it hasn’t been updated in a while, it still has fantastic information. I can’t tell you how many times I have visited that website.
Without further ado, let’s get started.
Since our first interview in 2015, you have earned a PhD in Ecology & Evolutionary Biology and now serve on the faculty at Texas State University. Describe your research focus for the readers.
My research is focused on understanding the evolutionary and ecological processes that have led fish to become the most species-rich group of vertebrates. To tackle this question, my lab utilizes a variety of techniques, such as genomics to understand the genomic basis of ecologically important traits, building evolutionary trees to calculate rates of speciation and evolution, high-speed video to study feeding kinematics, dietary studies to understand the consequences of dietary specialization on evolution, and utilizing medical imaging, such as microCT scanning, to study the morphology of fish specimens.
Besides the obvious, deeper understanding of biology and ecology gained by studying fish, how has your academic career changed your perspective on cichlids from that of a hobbyist?
I’m not necessarily sure it has. From my interactions with folks in the cichlid hobby, they seem to understand that cichlids are special in terms of ecology and evolution. I think most cichlid hobbyists appreciate the stunning diversity cichlids display—both in terms of the sheer number of species (described cichlids are over 4% of the ~37,000 scientifically described fish species) as well as the array of different colors, shapes, and unique behaviors that occur within the family. Similarly, many hobbyists also appreciate how interesting it is that many lakes harbor species, descended from a common ancestor, that have evolved a diversity of specializations and lifestyles over a short timescale (the definition of adaptive radiation), such as the cichlids of Lake Victoria, Lake Malawi, and Lake Tanganyika.
This diversity is what makes cichlids a fantastic system in which to study the ecological and evolutionary drivers of biodiversity and is why scientists use them to do such. This appreciation and interest for cichlids in the aquarium hobby, as well as the prevalence of cichlids in just about every pet store, also makes them a fantastic facilitator for me as a researcher to communicate science and general knowledge of ecology and evolution to the public.
Perhaps where I may deviate from a cichlid hobbyist is that I am really interested in quantifying how unusual cichlids are relative to patterns of ecological and evolutionary diversity displayed in other groups of fishes and what factors have led cichlids to display this exceptional diversity. I also deviate from die-hard cichlid keepers in that I am really interested in hybridization in cichlids. I want to stress this is natural hybridization, and not hybridization in captivity, which can have some major consequences as it relates to maintaining pure breeding stocks in the aquarium hobby, especially for at-risk cichlid species.
The more we investigate the genomics of cichlids, we find that natural hybridization plays a major role in cichlid diversification. It provides a means of transfer for ecologically important genetic material and may generate novel morphologies that may be able to exploit a previously unexploited ecological niche.
I think one aspect many hobbyists struggle with is understanding morphology, specifically sexual dimorphism. Can you describe for hobbyists what this means and provide an example or two with a cichlid species?
Morphology is the study of the form and structure of organisms (both internal and external) and is critical to our understanding of taxonomy, evolution, and function. Sexual dimorphism is a morphological phenomenon in which different sexes of the same species display different morphologies. Sexual dimorphism can occur in several different ways.
Perhaps what cichlid hobbyists may be most familiar about is sexual color dimorphism, in which the sexes display different colors. Sexual selection is common in cichlids, and coloration is known to play a large role in mate choice. There are a few cichlid species in which the sexes are vastly different in terms of coloration. For example, many cichlids, especially haplochromine species, have males that are quite colorful, while the females may be rather plain in color. Males may also have eggspots on their anal fins, which are used to attract females and increase fertilization rates. However, in some species females are more colorful than males. For example, the West African cichlid genus Pelvicachromis, the Central American cichlids of genus Amatitlania, and several South American Crenicichla species (or those formerly classified as Crenicichla as there has been a recent taxonomic revision) often have females that have a colorful belly used in courtship displays to attract males and signal they are ready to spawn.
Besides color, sexual dimorphism can be found in other morphological structures. For example, it is not uncommon for male cichlid species to develop longer extensions to their dorsal, anal, and caudal fins relative to females or a large nuchal hump, such as in species of Amphilophus and Cyphotilapia genera. There is also some evidence for differences in the skeletal and muscular elements of the pharyngeal jaws between the sexes of some cichlid species that use the pharyngeal jaws to generate sound during courtship.
Sexual dimorphism can also be as simple as vast differences in adult sizes between sexes. A good example of this is the Lake Tanganyika cichlid Neolamprologus callipterus, which is a shell dweller. Females are quite small in this species, whereas males are much larger and use their large bodies to pick up shells (and occasionally females) from rival male nesting sites.
A couple of years ago, you co-authored a journal article where you explored the relationship between morphology and feeding guilds (herbivores, piscivores, etc.). Though that study didn’t focus on cichlids, how might the findings inform conservation efforts with respect to human impacts on cichlid ecosystems?
We investigated patterns of morphological evolution as it relates to feeding guilds across coral reef-associated fishes. Specifically, we investigated patterns of morphological evolution and morphological diversity in fishes feeding at different levels of the food chain across reef fishes. Within populations of species, there is a pattern, in which populations that are more generalized tend to display more morphological variability than species which are more specialized, which has been coined the “niche variation hypothesis”. We decided to test the niche variation hypothesis, but at the species level rather than within a population across reef fishes. We found that contrary to the expectation of the niche variation hypothesis, reef fishes that are at the extremes of the food chain (i.e. strict herbivores and top-level predators feeding on other fishes) with narrow diet breadths actually had more functional diversity and the fastest rates of evolution. Omnivorous fishes, which have the broadest diet breadth as they exploit many prey items in their diet, had the lowest rates of evolution and functional diversity.
Fish at the extremes of the food chain also play important roles in reef function. For example, herbivores help control algal growth allowing for coral colonization and growth, and top-level predators help maintain populations in healthy coral reef ecosystems. However, these two groups are also heavily exploited as game fishes and food fishes (for example, parrotfishes, groupers, and jacks) and face overfishing pressure. The targeted removal of these species from coral reef ecosystems wouldn’t just remove the species, but also a large amount of functional diversity that occurs on coral reefs.
If you could only ever study one genera of cichlids, which would it be and why?
I’m going to cheat on this one and say Haplochromis. It is a catch-all genus in need of taxonomic revision with several hundred species, so, in the future, many will probably be reclassified into either new or resurrected genera. From the perspective of an evolutionary biologist, Haplochromis is a fascinating genus to study. It is the main genus in Lake Victoria. Lake Victoria is a very young lake, likely 15,000-100,000 years old, yet it contains several hundred cichlid species. This represents likely the fastest rates of speciation documented in vertebrates. This group is a fantastic system to understand how biodiversity is generated over short periods of time as well as the ecological and evolutionary dynamics of rapid speciation.
You told me during that first interview that you thought you had bred at least 130 species of cichlids. What is one particular species that stands out as being more difficult or surprising with respect to spawning efforts (either yours or theirs) and why?
I’d say Mikrogeophagus ramirezi. I have had several wild pairs spawn, but it is almost like they do not know how to be parents. They inevitably always either eat their spawn/fry, completely abandon them, or just don’t clean or fan the eggs and remove bad ones. What I find hilarious about this is that their sister species (closest relative) is the Bolivian ram, Mikrogeophagus altispinosus, which is one of my favorite fishes to keep. Bolivian rams in my experience are great parents and a lot less finicky than M. ramirezi. In my experience, they also display more interesting behavior and are more active in aquariums than M. ramirezi.
Given your vast experience working with cichlids, what are two pieces of advice you would give hobbyists new to this family of fish?
Get yourself involved in an aquarium club. They are usually quite welcoming, and there is a lot of information about keeping fish from interacting with these folks that you may not find online (or at least information that has a much better chance of being factual). It also usually gets you access to some neat fish that you may not necessarily have lines for. It’s also a way to network with scientists like me and learn more about the biology of the fish you are interested in.
The other would be to think more about conservation. For example, cichlids face a variety of threats, including habitat loss, climate change, and overfishing. If you care about these fish, think about giving to conservation-oriented groups that aid in biodiversity conservation efforts, supporting researchers studying at-risk fish, or in general, being more eco-conscious. There are also some cool conservation efforts happening in aquarium clubs that you can participate in, such as the CARES program.
Dr. Ron Coleman is one of your mentors. I had the privilege of interviewing him back in August. Both of you have served on the American Cichlid Association Board of Trustees. What should hobbyists who want to join a cichlid club or organization know or understand about serving such leadership roles?
I’d echo a lot of what Ron has said and sort of follow my response to the previous question. There are some great relationships that can be cultivated and knowledge that can be acquired that is only really available through aquarium clubs. I think being a part of both local and national clubs is important.
I’m a life member of the Greater Chicago Cichlid Association (though no longer living in Illinois) and still interact with folks in that club, as well as a member of the Hill Country Cichlid Club, which will help put on the American Cichlid Association convention this year. I’ve also been a member of the Pacific Coast Cichlid Association and Sacramento Aquarium Society while I was out in California for college. I’ve been a member of the American Cichlid Association for over a decade.
Aquarium clubs draw a diverse audience and allow you to interact with all sorts of folks associated with fish from hobbyists and scientists to those on the commercial side of the hobby. They also provide unique opportunities, such as collecting trips, box swaps, and rare fish auctions. I think one thing lacking in a lot of current clubs is a younger crowd, and I’d strongly encourage younger folks to make their voices heard to help guide the future of the hobby.
Thanks so much for agreeing to another interview. Anything we didn’t discuss about the world of cichlids here that you would like to mention?
For those interested in the work my lab does, you can check out my Google Scholar page for a list of articles (https://scholar.google.com/citations?user=m3ZGqFwAAAAJ&hl=en) as well as my website (https://fish4thought.wordpress.com/). I am also actively recruiting graduate students to my lab who are interested in conducting research on fish evolution and ecology, and those interested should email me.