SushiShef
New Member
Hello Everyone,
tl;dr - Mantis shrimp are not living for more than 6 months. Need advice.
I am involved with the maintenance and upkeep of an aquarium system in a facility that deals with mantis shrimp (Odontodactylus scyllarus). The system had successfully kept and maintained mantis for 8 or 9 years before it was moved to another facility (mine) in 2022. While I was not the one primarily in charge of the tanks when they arrived, I have participated in conversations regarding their maintenance. If you weren't able to tell from the title, it hasn't been going so well. Recently, I have stepped up to try to figure out some of the issues regarding the tanks in hopes to keep our specimens healthy and alive for an extended period of time. Any help or input is appreciated.
A brief history of the tanks and our mantis:
The tanks were set up by a trusted professional in mid-late 2022. We have 6 ~30 gallon acrylic tanks that are mounted onto 10-foot vertical racks facing a hallway window. There is a 2 pump system and a sump for each pump. One pump maintains cold intertidal conditions (~65° F) and the other maintains tropical reef-like conditions (~78° F). Both pumps cycle the same saltwater that is made weekly in a separate 50 gallon bucket, with salinity set to around 32-34 ppt before being added. When the tanks were first built, they were filled with living sand and decorated with coral that was sourced from tanks that had previously (and successfully) held mantis. There are also UV LEDs above each tank that we initially had on a 8/16 hour on/off timer. It should be noted now that the water is constantly tested for appropriate conditions every 1-2 days; more details about this later. With this setup, we were able to maintain 6 mantis for approximately 6 months with little to no problem.
During this period, we fed the mantis clams and frozen krill from local supermarkets. Around 3 months in, we began to notice that green/brownish algae began would grow on the walls of the tank when the UV lights were on. To clean them, we would scrape off the growth from the walls and let them drain into the skimmers and pumps that would filter the gunk from there. However, the rate of growth increased. To counteract this, we kept the UV lights off instead of running them on a timer. After some time, the mantis began to lose their appetite and we lost our first one shortly after. Over the next couple of weeks, we had lost all 6 of our mantis.
We cleaned out the tanks as much as we could before we got the next batch. These mantis lasted a decent while -- until April 2023 -- before disaster struck. We had an auto refill system for our sea water at the time that was hooked up to the building's DI water supply. Without any prior notice, the building ran hydrogen peroxide (H2O2) through the system in order to clean the pipes. All of our mantis died again over the course of the next month. We again cleaned up the tanks, cycled the water, and introduced more mantis, but those also didn't last longer than 3 months.
We took the opportunity to reset the tanks and update our pump system. We assumed that the H2O2 had killed the bacteria present in the live sand so we removed about 50% of it and replaced it with a new batch of live sand. Along with this, we upgraded the pumps for the tanks because the flow for our top most tanks were low. Wavemakers were also added to simulate more sea-like conditions and to keep the tanks cleaner. The sump was updated with better protein skimmers and biofilters were added to the sump. Multiple (I think 3 or 4) water changes were done over the course of 2 weeks in order to purge the system before we started redosing and preparing the final water for the next batch of mantis. Those mantis arrived around December of 2023 and the last one from that batch passed 2 weeks ago.
We just got 4 more mantis this week after doing the normal cleaning and cycling of water. With this batch of mantis, we've switched to feeding them frozen blocks of squid from an aquarium store instead of the supermarket krill. Additionally, we also introduced 3 Damselfish into the system as suggested by the owner of said store. These are kept separate from the mantis but in the same tanks in order to act as a control for our water; they are our "canary in a coalmine." The first damsel died 2 days after being introduced to the tank. Could be chalked up to failed acclimation as the other 2 are still alive, but we'll keep monitoring.
Water Chemistry
Now, one of things we've prioritized since the beginning is maintaining the correct water chemistry in the tanks. In this regard, we have many many tests to check the pH, KH, GH, Nitrites, Nitrates, Mg, salinity, etc. of the tanks. These are either API 5-in-1 tests, Saysummer 7-in-1 tests, and individual tests from API and Salifert. On average, our tests have had the following results:
pH: 7.7-8 | KH: 50-70 ppm (API/Saysummer)/9-10.5 dKH (Salifert) | GH: 150-180 ppm | NO2: 0 | NO3: 0-40 (varies on water change)
These are the things we monitor on the day by day. The water is changed every week, if not, every other week to maintain these values. We prepare 50 gallons of water with Red Sea Coral Pro salt and bring the salinity up to 30-32 for each change. The sumps are also filled regularly to ensure the pumps don't run dry.
Potential Problems
Now, we've consulted multiple people about the possible causes of the relatively frequent doom of our mantis, but nothing that has been suggested has kept them alive for more than a couple months. These were our problems and suggested solutions (that I remember at the moment):
Fast Algae Growth - Turned off the UV lights
High NO3 - We upped the frequency of our water changes to every week, if not every 2 weeks
Possible Shell Rot - confirmed that none of the mantis had this
High Stress due to Light - One of the things that we've read most recently on these forms and online is that mantis are sensitive to light which heightens their stress. The tanks they are in have face a window that opens into a hallway with motion activated light. Throughout the day, the hallway lights are relatively sporadic due to the traffic which led us to believe that the mantis have been restless. In addition, there was a monitor for another instrument that would be fairly bright at night. To alleviate this, we've temporarily put cardboard on the side with the window and covered the monitor when not in use.
High Stress due to Territorialism - Our current setup has one large, horizontal tank divided into 3 sections with dividers. The territorial nature of the shrimp may make it hard for them to cohabitate a single tank, even with the dividers we currently have set up. The fact that multiple shrimp live in (very) close proximity to each other may be stressing them out much more than they can handle. With the most recent batch, we have left the middle sections of the tank empty to prevent them from being in directly adjacent sections. This is the spot where we put the damsel in.
Right now, this is all I can think of writing but may update this post as details arise in my mind. I've been asked to not include any pictures of the facilities unfortunately but any comments or questions are welcome. I will try to be as descriptive and responsive as I can.
Thank you everyone in advance for your help and I look forward to the discussions.
tl;dr - Mantis shrimp are not living for more than 6 months. Need advice.
I am involved with the maintenance and upkeep of an aquarium system in a facility that deals with mantis shrimp (Odontodactylus scyllarus). The system had successfully kept and maintained mantis for 8 or 9 years before it was moved to another facility (mine) in 2022. While I was not the one primarily in charge of the tanks when they arrived, I have participated in conversations regarding their maintenance. If you weren't able to tell from the title, it hasn't been going so well. Recently, I have stepped up to try to figure out some of the issues regarding the tanks in hopes to keep our specimens healthy and alive for an extended period of time. Any help or input is appreciated.
A brief history of the tanks and our mantis:
The tanks were set up by a trusted professional in mid-late 2022. We have 6 ~30 gallon acrylic tanks that are mounted onto 10-foot vertical racks facing a hallway window. There is a 2 pump system and a sump for each pump. One pump maintains cold intertidal conditions (~65° F) and the other maintains tropical reef-like conditions (~78° F). Both pumps cycle the same saltwater that is made weekly in a separate 50 gallon bucket, with salinity set to around 32-34 ppt before being added. When the tanks were first built, they were filled with living sand and decorated with coral that was sourced from tanks that had previously (and successfully) held mantis. There are also UV LEDs above each tank that we initially had on a 8/16 hour on/off timer. It should be noted now that the water is constantly tested for appropriate conditions every 1-2 days; more details about this later. With this setup, we were able to maintain 6 mantis for approximately 6 months with little to no problem.
During this period, we fed the mantis clams and frozen krill from local supermarkets. Around 3 months in, we began to notice that green/brownish algae began would grow on the walls of the tank when the UV lights were on. To clean them, we would scrape off the growth from the walls and let them drain into the skimmers and pumps that would filter the gunk from there. However, the rate of growth increased. To counteract this, we kept the UV lights off instead of running them on a timer. After some time, the mantis began to lose their appetite and we lost our first one shortly after. Over the next couple of weeks, we had lost all 6 of our mantis.
We cleaned out the tanks as much as we could before we got the next batch. These mantis lasted a decent while -- until April 2023 -- before disaster struck. We had an auto refill system for our sea water at the time that was hooked up to the building's DI water supply. Without any prior notice, the building ran hydrogen peroxide (H2O2) through the system in order to clean the pipes. All of our mantis died again over the course of the next month. We again cleaned up the tanks, cycled the water, and introduced more mantis, but those also didn't last longer than 3 months.
We took the opportunity to reset the tanks and update our pump system. We assumed that the H2O2 had killed the bacteria present in the live sand so we removed about 50% of it and replaced it with a new batch of live sand. Along with this, we upgraded the pumps for the tanks because the flow for our top most tanks were low. Wavemakers were also added to simulate more sea-like conditions and to keep the tanks cleaner. The sump was updated with better protein skimmers and biofilters were added to the sump. Multiple (I think 3 or 4) water changes were done over the course of 2 weeks in order to purge the system before we started redosing and preparing the final water for the next batch of mantis. Those mantis arrived around December of 2023 and the last one from that batch passed 2 weeks ago.
We just got 4 more mantis this week after doing the normal cleaning and cycling of water. With this batch of mantis, we've switched to feeding them frozen blocks of squid from an aquarium store instead of the supermarket krill. Additionally, we also introduced 3 Damselfish into the system as suggested by the owner of said store. These are kept separate from the mantis but in the same tanks in order to act as a control for our water; they are our "canary in a coalmine." The first damsel died 2 days after being introduced to the tank. Could be chalked up to failed acclimation as the other 2 are still alive, but we'll keep monitoring.
Water Chemistry
Now, one of things we've prioritized since the beginning is maintaining the correct water chemistry in the tanks. In this regard, we have many many tests to check the pH, KH, GH, Nitrites, Nitrates, Mg, salinity, etc. of the tanks. These are either API 5-in-1 tests, Saysummer 7-in-1 tests, and individual tests from API and Salifert. On average, our tests have had the following results:
pH: 7.7-8 | KH: 50-70 ppm (API/Saysummer)/9-10.5 dKH (Salifert) | GH: 150-180 ppm | NO2: 0 | NO3: 0-40 (varies on water change)
These are the things we monitor on the day by day. The water is changed every week, if not, every other week to maintain these values. We prepare 50 gallons of water with Red Sea Coral Pro salt and bring the salinity up to 30-32 for each change. The sumps are also filled regularly to ensure the pumps don't run dry.
Potential Problems
Now, we've consulted multiple people about the possible causes of the relatively frequent doom of our mantis, but nothing that has been suggested has kept them alive for more than a couple months. These were our problems and suggested solutions (that I remember at the moment):
Fast Algae Growth - Turned off the UV lights
High NO3 - We upped the frequency of our water changes to every week, if not every 2 weeks
Possible Shell Rot - confirmed that none of the mantis had this
High Stress due to Light - One of the things that we've read most recently on these forms and online is that mantis are sensitive to light which heightens their stress. The tanks they are in have face a window that opens into a hallway with motion activated light. Throughout the day, the hallway lights are relatively sporadic due to the traffic which led us to believe that the mantis have been restless. In addition, there was a monitor for another instrument that would be fairly bright at night. To alleviate this, we've temporarily put cardboard on the side with the window and covered the monitor when not in use.
High Stress due to Territorialism - Our current setup has one large, horizontal tank divided into 3 sections with dividers. The territorial nature of the shrimp may make it hard for them to cohabitate a single tank, even with the dividers we currently have set up. The fact that multiple shrimp live in (very) close proximity to each other may be stressing them out much more than they can handle. With the most recent batch, we have left the middle sections of the tank empty to prevent them from being in directly adjacent sections. This is the spot where we put the damsel in.
Right now, this is all I can think of writing but may update this post as details arise in my mind. I've been asked to not include any pictures of the facilities unfortunately but any comments or questions are welcome. I will try to be as descriptive and responsive as I can.
Thank you everyone in advance for your help and I look forward to the discussions.
