Guitar, Shovel or Both?

The Guitar Shovelnose Ray (Pseudobatos lentiginosus) is a member of the family Rhinobatidae which are commonly known as guitarfishes. Guitarfish is just a somewhat cooler common name for shovelnose sharks or rays, which are a group of cartilaginous fishes (fish with cartilage instead of bones) like sharks, skates, rays and sawfish.

Guitarfish have scales we call denticles (yes dent, like the dentist – because these scales resemble small teeth) and the first record we have of their existence comes from the Ordovician period which started 488 million years ago. While these primitive early fishes weren’t guitarfish, the lineage is very old - seeing as how fish are accepted to have arrived on the scene about 485 million years ago. The Mesozoic era started about 250 million years ago, and this is where we have the first solid evidence of skates and rays. To put that in perspective mammals have existed for about 178 million years and modern humans potentially as little as 100,000 years, so show some respect for these creatures that have survived a couple mass extinctions!

Guitar Shovelnose Rays have the potential to get almost 30 inches long; some of the larger fishes in their family (Rhinobatidae) can reach almost three meters! That said, most members of this species probably won’t get much over 20 inches in total length. Guitar Shovelnose are usually light brown and spotted on their dorsal (top) side. Their ventral (underside) is paler, usually white or yellowish. The body shape, unsurprisingly, is that of a fancy electric guitar with a sharp, almost triangularly shaped head portion tapering to the caudal fin (tail) with two dorsal fins (the ones on top) before it. This group of fish is easily recognizable, making it pretty obvious as to how they got their common names of guitar or shovelnose fishes.

Guitar Shovelnose Rays are found in the Western Atlantic Ocean, from the Mid-South of the Eastern seaboard of the United States to the Yucatan Peninsula in Mexico where they are relatively uncommon. These fish prefer shallow waters and are rarely found deeper than a hundred feet down. They like sandy bottoms where their flat bodies can easily hide in with the substrate where they like to bury themselves for protection. Rocky substrates or substrates with too much vegetation can prevent this behavior. Sometimes they can be found relatively exposed but with vertical cover such as an overhang of rock to protect them from above.

An appropriately sized aquarium for a Guitar Shovelnose Ray will need to be pretty large. Small pools or indoor ponds may be a better choice. Despite the fact that these fish are relatively sedentary they will need at least a four-foot diameter pool or an aquarium of equal minimum dimensions (4x4’). Guitarfish as large predators will also demand a lot of aeration and filtration. The ocean is a very stable place, and waste is immediately diluted into the volume of the ocean (you’ve heard the phrase “the solution to pollution is dilution” when it comes to water changes – well the ocean is pretty dilute when you consider how big it is compared to fish waste). This unfortunately is not the case in the home aquarium and so fish that eat and produce a lot of waste need to be countered with powerful filtration and aeration.

This group of fish is also known to produce ammonia more than most aquarium fish, freshwater or saltwater; biological filtration should be oversized as much as possible. The bacteria in this type of filtration will also consume oxygen – so aeration and surface area of filtration and the habitat should be maximized for as much off-gassing of co2 as possible. Heating and/or chilling may be necessary depending on where you live and temperatures for these fish should be kept in the mid or low seventies. The substrate should be fine and smooth so as to prevent them from injuring themselves when they try to bury themselves in it as they do in the wild. Any rock in the aquarium (largely unneeded) should be very secure to prevent them from falling over on your prized ray.

Housing the rays with fish like wrasses can help with clean up as they eat small pieces of food the rays miss and the mess the rays make. This is important because a cleanup crew in a habitat with these guys probably won’t last long because these fish mostly consume invertebrates and their diet in captivity should reflect that. If you decide to attempt a clean-up crew in a display with a Shovelnose, keep an eye on what works and be prepared to continually add more.

A diverse selection of mostly whole foods such as shrimp, clams, mussels, etc should be offered. Offerings of cut whole fish will also likely learn to be accepted as your pets come to know you. An important consideration when it comes to any elasmobranch in captivity is their need for supplemental vitamins and minerals. There are shark multivitamins available, and a small amount of research will guide you to something suitable for your fish. This should not be overlooked, iodide deficiency in captive elasmobranchs can cause them to develop goiters which are unsightly and bad for your fish. Recent studies show that having high levels of nitrate in the display can also affect the fish's ability to absorb iodide – so keep your water clean and your fishes diet balanced for their best health.

Breeding these fish in a large enough pool is an attainable goal for the elasmobranch hobbyist. Guitar Shovelnose Rays give birth to live young and are viviparous meaning that the babies develop inside the mother – rather than developing in an external egg like many other fishes. These fish exhibit aplacental viviparity (meaning that the mother nourished them without a placenta like in humans). They do this by feeding on their yolk and then through absorption of uterine fluid that is enriched to be sustaining for the young rays. They are known to give birth to up to six live pups. Males become sexually mature at around 60% of their maximum size. A quite large aquarium with good conditions and good feed should be enough to encourage them to breed – water temperatures may need to vary along with day length to encourage them further if simply being in good condition is not enough to trigger them. Males should be outnumbered by females to prevent them from being overly harassed. One male per three females should be the highest ratio of males to females, and males are easily distinguished from females by the presence of claspers (elongated tube-like structures off the pelvic fins).

Guitar Shovelnose Rays are an intriguing challenge for someone with the dedication for a large aquarium, and the ability to maintain the excellent water quality they are used to in the ocean. Visually unique, and an excellent biological conversation piece, the budding elasmobranch hobbyist should consider these fish for a unique breeding challenge. So, if this sounds like you, call your local fish store and ask them to order you a group of sustainably sourced Guitar Shovelnose Rays from Quality Marine today!