yumas and lighting

[scottr0076]

Gday hows it going im new to the forum, just a quick question, im have some proble with my yuma's thay are fading and eventually dying. My tank is 40inches hight 24inches deep and 73.5 wide, the rics are at the bottom of the tank on substrate, im using 2 X 400w MH 120 inches off the top of the tank and they are still bleaching. I have checked all my perametres all ok. Any help would be great

 

[Tallinu]

Gday sir,

I keep mine 27 inches under 250 watt hqi 14k bulbs. You have a 40 inch tall tank and lights 120 inches above for a mean distance of 160 inches if you have no substrate. Thats roughly 13 and a half feet. If you intended those figures and they are not a typo, thats a long ways. 400 watt metal halides are strong but not that strong. You need to bring them much closer. maybe 2 feet off the top of your tank.

You also say 24 inches deep. Height and depth are the same. One of those measurements must be length and I'm assuming 40 height was meant as width front to back? that would drop almost a couple of feet off my comments. At any rate if your light shy put them a couple of feet above your tank, not 10 feet plus.

 

[Tallinu]

I forgot to add, feed the yuma's you have left. They are like anemone's and are probably starving for anything, light or food. Mysis shrimp are good but I find they will target feed almost anything you feed fish or corals. If you adjust your lights they will need to be prepared in advance by moving into shaded positions for light shock. Only a healthy yuma will adjust rapidly to significant changes in light.

 

[scottr0076]

sorry my mistake the lights are 12 inches above the tank not 120 and 24 inches deep or the depth of the tank we use that turm in australia as well either top to bottom or front to back in this case front to back

 

[Tallinu]

Then the problems you are facing are the same ones most people face when trying to keep Yuma's. I have over 18 yuma's now of various sizes that I've managed to keep going and am always on the look out for more. Aside from the critical break in period for new specimens I have no more troubles. The light that you have is pretty intense. And for whatever reason, yumas do not take well to strong light even though the power of the sun is much greater. They do adjust and thrive when they are healthy though. Set up, if you do not have already, some areas of indirect lighting. Basically areas of shade. This will give the zooanthellae a chance to adjust to your spectrum of lighting. Feed your yumas as if they were anemones. They don't always eat when they are not well but if they do then your chances are very good that your specimens will survive. Ensure that they do not get a large flow of current. Good water movement is great for them but the polyp should be stationary and not flapping around to much at the edges. Keep your salinity fairly level with top offs. Large swings can push them over the edge when they are on the ropes.