What is this urchin doing?
- Thread starter angelap
- Start date
ophiura
Active Member
Well, it is not necessarily good water quality as many of these guys need virtually no reason to start spawning...but they can spawn as easily due to sudden stress as happiness. In fact, scientists do some wacky things to get some echinoderms to spawn (temp shock, aggitation, light shock), but that is not for the public boards 
Anyway, good water quality should be measured in part by having good test kits and part by looking at the tank- algae balance and animal behavior. But some animals due quite well in 'dirty' tanks, so that is a big topic too. Anyway, it was most likely a spawning male urchin, and time for a good free meal for the tank but check water tests for more info on the water quality
Anyway, good water quality should be measured in part by having good test kits and part by looking at the tank- algae balance and animal behavior. But some animals due quite well in 'dirty' tanks, so that is a big topic too. Anyway, it was most likely a spawning male urchin, and time for a good free meal for the tank but check water tests for more info on the water quality 
bang guy
Moderator
Originally posted by ophiura
but they can spawn as easily due to sudden stress as happiness.
Pardon Ophiura, but I have to disagree here...
IMO Captive Urchins are many many times more likely to spawn due to adverse water contitions than to healthy conditions. Most likely a sudden change in Salinity. Of course, for the reasons they would spawn in nature I defer to your wisdom.
Guy
ophiura
Active Member
Bang, I don't think we disagree at all! In nature, urchins are often quite seasonal, and spawn at particular times of the year which is generally correlated to light and/or temperature cycles. But in our tanks, alas, things are not as stable, and they will spawn rather more randomly, indeed due most likely to sudden 'stresses' such as- as mentioned- salinity changes. Correlation with such sudden changes (eg after a water change) would probably be quite high. I suspect the majority of spawning in captivity is due to this- or something like temperature shock- though undoubtedly there are some very stable systems that still have individuals that will spawn, especially with species that don't show any particular trend in reproductive cycles.
But I don't necessarily think it is terribly tied to something like nitrate levels that is often implied in the phrase 'good water quality.' Angela, did you recently do a water change, top off or anything?
In nature, urchins are often quite seasonal, and spawn at particular times of the year which is generally correlated to light and/or temperature cycles. But in our tanks, alas, things are not as stable, and they will spawn rather more randomly, indeed due most likely to sudden 'stresses' such as- as mentioned- salinity changes. Correlation with such sudden changes (eg after a water change) would probably be quite high. I suspect the majority of spawning in captivity is due to this- or something like temperature shock- though undoubtedly there are some very stable systems that still have individuals that will spawn, especially with species that don't show any particular trend in reproductive cycles. But I don't necessarily think it is terribly tied to something like nitrate levels that is often implied in the phrase 'good water quality.' Angela, did you recently do a water change, top off or anything?
angelap
Member
Thanks for the replys everyone. I did do a 10 gal water change the end of June. Test are as follows:
Ammonia: 0
Nitrite: 0
Nitrate: 10
Ph: 8.2
Until about 2 weeks ago, this was all I was testing for. I started dosing calcium then, and today calcium test showed 600. (I'm working on getting that down)
I don't have a test yet for Alk.
Other than that, no other changes lately besides adding a couple new corals that are doing great!
Again, thanks so much for taking time to reply!
Angela
Ammonia: 0
Nitrite: 0
Nitrate: 10
Ph: 8.2
Until about 2 weeks ago, this was all I was testing for. I started dosing calcium then, and today calcium test showed 600. (I'm working on getting that down)
I don't have a test yet for Alk.
Other than that, no other changes lately besides adding a couple new corals that are doing great!
Again, thanks so much for taking time to reply!
Angela