Photography Equipment
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Condition Before Tank Introduction
After purchasing from the aquarium store, it took about 1 hour before placing the entire bag into the tank for temperature acclimation. Before introduction, the one with abnormal coloration showed signs of lying on its side with low activity. The other two were egg-carrying females with high activity.
Tank Introduction Method
For photography purposes, a T8 fluorescent tube was turned on this time. Otherwise, a dim lighting environment would be better to reduce stress in the organisms. Temperature acclimation took about 1 hour, water acclimation 30 minutes, with the added water volume approximately 1:1 with the water in the bag.
Why Did It Die Right After Purchase?
Since this was my first encounter with Caridina leucostica, I didn't think much at the time of purchase, only considering how many to buy, and then asked the shop owner to catch them after deciding. In retrospect, there were many things that could have been done better. For example, like fish, shrimp should be transported in rounded-corner bags, and nets or aquatic plants should be placed in the bag to allow the shrimp to cling, preventing excessive shaking during transport.
Of course, it's also possible that the shrimp itself was in poor condition, with low activity even at the aquarium store, which made it easy to catch. After death, the body showed a whitish, cloudy state, possibly related to bacterial infection.
Morphological Characteristics of Caridina leucostica
A total of 3 shrimp were purchased this time. During temperature acclimation, one was found to have distinctly different coloration from the other two, initially thought to be a different species. After consulting the "Taiwan Freshwater Fish and Shrimp Atlas," it appeared more similar to "Caridina sp." in the book.
Caridina sp. (formerly known as "平角米蝦"), catadromous, distributed in Lanyu (Orchid Island) and Hengchun Peninsula, prefers to inhabit mid-upper streams and is accustomed to activity among gravel (Lin Chun-ji, 2007).
In the latest 2020 shrimp atlas "Taiwan Freshwater and Estuarine Fish and Shrimp Atlas," the subject of this observation is no longer called "Caridina sp.," but is officially classified as "Caridina leucostica." Caridina leucostica is catadromous, inhabiting highly concealed areas in mid-lower reaches of rivers, with red and dark brown mottling on the body sides. Its appearance is similar to the large-rostrum shrimp (Caridina grandirostris), but can be distinguished by the number of rostral teeth at the tip: Caridina leucostica has 3 rostral teeth at the tip, while Caridina grandirostris has 2 (Zhou Ming-tai, Gao Rui-qing, Zhang Rui-zong, Liao Jun, 2020).
Macro Observation
The following photos were taken underwater using a super objective lens. During shooting, a large number of shrimp leeches (Branchiobdellida) were observed moving on the shrimp's body surface.
Post-mortem Coloration
The shrimp's chromatophores contract and change in response to light sources. From this Caridina leucostica, blue, yellow, and red chromatophores can be observed.
The shrimp's body coloration changes as the time after death increases. The image below shows one of the post-mortem colorations.
Live Specimen Coloration
The image below shows the only remaining Caridina leucostica in the tank, with coloration different from before tank introduction.
Activity After Tank Introduction
During the same period, 1 flame chameleon (Badis badis) and 3 galaxy rasboras (Celestichthys margaritatus) were also added, and all are currently doing well. The video later shows the reaction and behavior of pistol shrimp (Alpheidae) being introduced to the tank.
Reference Atlas
1. Taiwan Freshwater Fish and Shrimp Atlas (Volume 2) (Published June 2007)
2. Taiwan Freshwater and Estuarine Fish and Shrimp Atlas (Published September 2020)
References
Lin Chun-ji (2007) Taiwan Freshwater Fish and Shrimp Atlas (Volume 2), CommonWealth Publishing.
Zhou Ming-tai, Gao Rui-qing, Zhang Rui-zong, Liao Jun (2020) Taiwan Freshwater and Estuarine Fish and Shrimp Atlas, Morning Star Publishing.