Anxious Jawfish? Afraid of the Dark?

[wpeterson]

Hey guys,

I'm having trouble with my Jawfish. Every night after lights out, he becomes anxious and leaves his burrow. He wanders around the tank hiding on top of the substrate and digging everything up. Despite having an established burrow, he re-digs new burrows each night and often ends up somewhere new.

We added a deep substrate that's 4-6" around the tank, deeper than the length of his body. We've reinforced all of our base rocks to allow him safe tunneling and added large amounts of small shells and coral rubble for him to build with (which he happily uses).

When I leave low-level lights on overnight, he stays in his burrow. But if I leave the lights off for the Corals photosynthesis cycle, he gets anxious and tears up the tank including attempts to jump (added a glass canopy to protect him). During the day he's happy, eats mysis/brine shrimp when fed and any copods/ampipods in the water column.

This is a recent problem that has only been happening the last 1-2 weeks since I changed the lighting cycle for our corals, with lights out from 10pm to 6am.

I have a 30 gal FOWLR aspiring to be a reef tank. We've had this system up for about 4 months with good water quality. We've introduced stronger lighting and two small coral frags two weeks ago.
- 20lbs of live rock, 6" live sand substrate.
- Yelllow Headed Jawfish
- 2 Paired True Percula Clowns
- Green Clown Goby
- 2 Scarlet Hermits, 2 Blue Leg Hermits, 1 Zebra Dwarf Hermit, 3 Peppermint Shimp, 5 Banded Trochus, 3 Nassarius, 5 Astrea
- 1" Green Leather Coral Frag
- 1" Green/Blue Ricordea Florida Frag

Water quality is good, we do small water changes 1-2 times a week. Current Readings:
- Salinity 1.025
- pH 8.3
- Ammonia: 0
- Nitrite: 0
- Nitrate: 0
- Phosphate: 0

Any advice is much appreciated. He seems anxious and we're pulling our hair out worrying about him and repairing his rampages on the substrates in the mornings.

Leaving moonlights on seems to keep him from misbehaving, but can't be healthy for coral growth.

 

[Marshall O]

How long have you had it? I found my Blue Spotted would wander around after lights out as well for the first few weeks I had him.

Also, what specific sand are you using? I have found that courser sand is better for Jawfish to make their burrows. My sand is on the fine side and so my BSJ has trouble getting his burrow the way he likes it.

 

[P-Nut]

My pistol shrimp does something similar. It has 4 caves, and switches around every other night.
It was covering all my corals with sand, but the I added small rocks so it woukd be able to build a cave that wouldn't collapse.

It still uses all its caves, but now it doesn't need to re-dig the caves every night.

 

[wpeterson]

Thanks, guys.

We've got a course substrate of black aragonite live sand. We bought a bunch of coral rubble, 1/2"-2" sized pieces of rock. I'll make sure to add more near these secondary burrows. He has a main burrow well reinforced with sand, rubble, and under a base rock.

 

[nemodan]

If leaving low lights levels all is OK, wouldn't be a good idea to have moonlights all night ?

They provide a very soft blue light. All my corals always had moonlight. That low level of light will not have any influence on coral photosynthesis. But will help the fish based on your comments.

 

[wpeterson]

If leaving low lights levels all is OK, wouldn't be a good idea to have moonlights all night ?

They provide a very soft blue light. All my corals always had moonlight. That low level of light will not have any influence on coral photosynthesis. But will help the fish based on your comments.

That was my original plan, but talking to some BRS coral experts convinced me this will hurt the dark cycle of photosynthesis for the coral zooxanthellae.

 

[Cherokee_Dude]

Not sure I'd agree with that assessment. The moon shows up pretty consistently in the Corals natural environment. A cheap single led moonlight would be fine.

That was my original plan, but talking to some BRS coral experts convinced me this will hurt the dark cycle of photosynthesis for the coral zooxanthellae.

 

[nemodan]

From: http://www.reef-eden.net/lighting.htm

.......In tropical climates where our corals originate, the day night cycle is a simple 12 hours of sunlight, and 12 hours of darkness. with short intermediate transitions as the sun rises and falls quickly on the horizon compared to its slower transition as we move north or south of the equator. Due to the relatively small amount of cloud cover at these latitudes its also allot more intense for longer periods of time, and nights are typically brighter during the peak periods of the Luna cycle. In simple terms this means that your average day night cycle on a reef, consists of around 10 hours of intense illumination, 2 hours of intermediate lighting at each end, and around 10 hours 'just' short of total darkness, dependant on the moons position in the sky...........

From: Moonlight Triggers Mass Coral "Romance" http://news.nationalgeographic.com/news/2007/10/071019-coral-spawning.html

............In today's issue of the journal Science, researchers reveal that they have isolated an ancient gene in the corals' DNA that can detect moonlight. By exposing corals to different colors and intensities of light, the team found that the gene—known as Cry2—was most active in Acropora corals during a full moon......