10 replies to this topic

[Joshaeus]

Hi everyone! Long time no post. I am working on setting up a 10 gallon planted tank and am trying to decide what I will keep in it. Would rainwater killies do well so long as I add a little salt (1/2 to 1 tsp marine salt per gallon?) to the water? Are they shy like bluefins are? And would any other native killies (sheepshead minnows, for instance) work in a 10 gallon, with or without a small amount of salt? Thanks

[Robert Lamb]

Sheepshead minnows will do great with or without salt as long as the ph is high

[Robert Lamb]

They also will do fine in a 10 as long as there is stuff to break the line of sight when they get to breeding

[Joshaeus]

Sheepshead minnows will do great with or without salt as long as the ph is high

 

 

They also will do fine in a 10 as long as there is stuff to break the line of sight when they get to breeding

Thanks! I could have sworn reading somewhere that sheepshead minnows (except for the freshwater subspecies) need a small amount of salt in their water to osmoregulate properly, but the amount required was so small that it was still practically freshwater (I believe a half teaspoon marine salt per gallon was sufficient?). The tank was going to be densely planted.

 

EDIT: I found the article; https://jeb.biologis...tent/215/7/1199

Evidently 'normal' sheepshead minnows need at least 2 mmol of sodium ions in the water in order to survive. Fortunately, that is a pitifully small amount of marine salt...I calculated it out and found that a half teaspoon marine salt per 4 liters would be ample to provide that.

Edited by Joshaeus, 17 June 2020 - 06:14 AM.

[swampfish]

Another option might be increase the amount of salt and use salt-tolerant plants such as Vallisneria, Najas, Java fern, and Java moss. My understanding that these plants commonly live in brackish water.

 

Phil Nixon

[Joshaeus]

Another option might be increase the amount of salt and use salt-tolerant plants such as Vallisneria, Najas, Java fern, and Java moss. My understanding that these plants commonly live in brackish water.

 

Phil Nixon

True...but I was hoping for a more diverse planting than that. 1/2 tsp marine salt per 4 liters provides more than ten times the 2 mmol sodium required by sheepshead minnows and is still effectively freshwater (about .58 ppt salinity), so that seems like a fair compromise for both plants and fish.

[Chasmodes]

I'm currently keeping 9 rainwater killies and one male sheepshead minnow in a 20g tank with oysters, mud crabs, grass shrimp and snails.   Everything is doing great.  The specific gravity is 1.012.  When I caught them, the SG was 1.009.  I have a macro algae (Ulva) in there that provides plenty of cover, but even without it, the sheepshead minnow, although a bully, never really hurt any of the rainwater killies.  He just harassed them.  Now, with the Ulva, that seems to have solved the problem.  Than might also work with multiple sheepshead minnows.  I haven't tried Valisneria yet, but maybe I will.

[Joshaeus]

I'm currently keeping 9 rainwater killies and one male sheepshead minnow in a 20g tank with oysters, mud crabs, grass shrimp and snails.   Everything is doing great.  The specific gravity is 1.012.  When I caught them, the SG was 1.009.  I have a macro algae (Ulva) in there that provides plenty of cover, but even without it, the sheepshead minnow, although a bully, never really hurt any of the rainwater killies.  He just harassed them.  Now, with the Ulva, that seems to have solved the problem.  Than might also work with multiple sheepshead minnows.  I haven't tried Valisneria yet, but maybe I will.

I'm curious...how long has the Ulva been in there, and is it growing? I was wondering about macro algae species that will take low salinities. (PS...Caulerpa prolifera is apparently tolerant of 20 ppt salinity, which comes to 1.015 specific gravity. 15 ppt, or 1.0113, was too low).

[Robert Lamb]

Can't say anything about ulva, but I keep cheatomorpha with my Cyprinodon rubrofluviatilis and have not had any die offs even when the water got down to a little under 1.004, although it does not grow much at that level.

[Joshaeus]

Can't say anything about ulva, but I keep cheatomorpha with my Cyprinodon rubrofluviatilis and have not had any die offs even when the water got down to a little under 1.004, although it does not grow much at that level.

Cool! On a reef forum I was able to talk with a member who was keeping a dedicated macroalgae tank...he found that macroalgae grew FAR better when he dosed small amounts of baking soda (enough to increase KH by about 1 degree's worth) daily. Macroalgae are apparently very good at using bicarbonate as a carbon source - he also had to start fertilizing the tank (like what one has to do with a high tech planted aquarium) to keep up with the resulting spike in nutrient requirements for the macroalgae. I wonder if something similar would help macroalgae kept in lower salinities...after all, carbonates were not dosed in any salinity tolerance experiment for macroalgae I have ever read about, and most of the carbonates in a brackish or marine tank are usually going to come from the salt.

[Chasmodes]

In my last tank, I couldn't keep Ulva alive, although, I could collect plenty of it.  Since then, I purchased a new light, and this batch is growing, even though I collected it just 3 weeks ago.  It's doubled in size.  My SG is now 1.012.  Last year, we had a ton of rain that kept the Chesapeake Bay SG down much more than usual.  At my collecting spots, the SG measured 1.007 to 1.009, and Ulva was everywhere.  I don't know the low tolerance range for Ulva though, but 1.009 is really low for those collecting spots.  That's why we had such a hard time collecting our blennies there.

 

I haven't dosed anything yet.  I'm not sure Ulva needs it though, but it wouldn't hurt to try.