How much can fish eat?

karimwassef

Active member
I have a ~400gal tank with a lot of tangs and herbivores
1 10" hippo tang
1 9" Red Sea sailfin tang
1 8" two stripe rabbitfish
1 7" Indian Ocean sailfin tang
1 7" Red Sea purple tang
5 6" yellow tangs
1 6" melanarus wrasse
1 6" starry blenny

So 12 mostly herbivores. I also have other pod and other foods.

There's the usual CUC with snails, crabs, shrimp, urchins, etc...

As my tank has gotten more algae free, I've been feeding more Nori.

At this point, I'm up to four full sheets a day. That seems like a lot (28 sheets a week, 120 sheets a month). They're on shielded clip so the fish have to literally pull it out of the grate openings to eat, so it doesn't go to waste. They consume all the nori daily. Half within the first hour, and the rest over the next 6 hrs of grazing. My skimmer, chaeto refugium, and ATS are keeping things clean... But I'm concerned with the trajectory.

Three months ago, I was at 1-2 sheets a week... They wanted more but they had enough algae to graze on.

So, the question: in the absence of algae in the tank, how much nori would 12 herbivores consume a day to be full?
 
Given the amount and size of the tangs I would say if anything they need more nori, not less. 5-6 sheets seems about right unless you are giving them a fair amount of other foods. How do the fish look? The tangs in particular should have a nice rounded shape in front of their dorsal fin and their stomach area should also have a nice rounded shape, not sunken in.
 
They look good to me.

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My overflow weir algal turf scrubber looks pretty healthy too though

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So maybe they're getting algae off the DT rocks too.

The only place there's still algae is against the top just before the end to end overflow weir. The biggest and most aggressive (sailfin, yellows, rabbit) were starting to do gymnastic swimming feats whenever a surge would come so they can eat the little bit of algae that's just out of reach. The surge raises the water level by 2" so they can get at it. That's when I started adding more Nori.
 
Given the amount and size of the tangs I would say if anything they need more nori, not less. 5-6 sheets seems about right unless you are giving them a fair amount of other foods. How do the fish look? The tangs in particular should have a nice rounded shape in front of their dorsal fin and their stomach area should also have a nice rounded shape, not sunken in.

So about half a sheet each per day?
 
The rabbitfish is voracious. It eats more than any other fish and grows the fastest. It was the same size as the IO sailfin when I got them together at about 1.5" each. Now it's an inch longer than the sailfin.
 
If you are going through that much nori it tells me you are not feeding the fish enough food in general. Try upping the amount of fresh food like oysters, clams, and shrimp. Your fish will thank you for it. Skip the pellets and flakes which are mostly over processed fish meal and wheat fillers.
 
I feed frozen foods: mysis (4 cubes/week) and cyclopese (3 cubes/week). The mysis gets garlicX and the cyclopese gets selcon.
I feed 60ml of phytoplankton a week = thick pod population = fat wrasses, mandarin, dottyback, jawfish
I feed one tablespoon of reef flake food a day
I feed one tablespoon of sinking pellets a week
I feed two teaspoons of powdered food for corals a week: one teaspoon of reef chilli and one of reef roids mixed in selcon and Restor.
 
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So I'm at 4 full sheets (7.5" x 8.3" sheets x 4 = 5g total dry) of Nori a day every day + 3 cubes every other day. Finally, there's some Nori left over at the end of the day...

But I think my sailfin is getting a belly?

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I would keep it at around 3-4 sheets a day, they are healthy though. I feed my 4" tang 1/2 sheet a day to give you an idea, but i dont have other algae in the tank, at least not in the dt
 
That Red Sea Sailfin is beautiful. I can't wait for mine Zebrasoma Tang to get that size. He is only 3 1/2 inches for now with a fat belly too. Your Tangs looks healthy to me.
 
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If I were you, I'd wouldn't wait another second and start treating for reef spiders!

What in the heck is that thing?

Tank looks great by the way!
 

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