Some plants getting black spots and small holes

[misterbiscuit]

I'm new here (hello 🙂), so apologies if I've posted this question in the wrong forum.

I've had my aquarium set up with real plants for quite a few months now, and things have been growing nicely and at a good speed.
However in the past few weeks I've started to notice some plants developing little black spots on them (at first I thought it was just some waste), but then it seems those little black spots turn in to actual small holes through the leaves.

I've been dosing fertilizer each week. I use TNC Lite as it seemed to get positive things said about it, and I went for the 'Lite' version as my tap water already has plenty of nitrates.

From what I've learnt so far there is some sort of deficiency in my water causing this to happen.
I was hoping for some advice on what I can do to fix it, as in should I dose more than I have been of TNC Lite, switch to a different fertilizer or do I need to do something else?

 

[dw1305]

Hi all,
Welcome to UKAPS. Do you have a Bristlenose (Ancistrus) catfish or Amano shrimps?

I use TNC Lite as it seemed to get positive things said about it, and I went for the 'Lite' version as my tap water already has plenty of nitrates....I was hoping for some advice on what I can do to fix it, as in should I dose more than I have been of TNC Lite, switch to a different fertilizer or do I need to do something else?

I'd try a complete fertiliser, <"TNC Complete"> perhaps?

I wouldn't worry too much about the nitrate (NO3-) or phosphate (PO4---) levels in your tap water, plants are <"pretty efficient at depleting nutrients"> and neither nitrate or <"phosphate"> is <"harmful to fish"> until you reach really high levels.

High nitrate (NO3-) levels are usually regarded as an indication of <"previous high levels of the (extremely toxic) ammonia (NH3) and nitrite (NO2-)">, but if you add them, via a water change or chemical fertiliser, <"they arrived as nitrate">.

cheers Darrel

 

[misterbiscuit]

Hi all,
Welcome to UKAPS. Do you have a Bristlenose (Ancistrus) catfish or Amano shrimps?

I'd try a complete fertiliser, <"TNC Complete"> perhaps?

I wouldn't worry too much about the nitrate (NO3-) or phosphate (PO4---) levels in your tap water, plants are <"pretty efficient at depleting nutrients"> and neither nitrate or <"phosphate"> is <"harmful to fish"> until you reach really high levels.

High nitrate (NO3-) levels are usually regarded as an indication of <"previous high levels of the (extremely toxic) ammonia (NH3) and nitrite (NO2-)">, but if you add them, via a water change or chemical fertiliser, <"they arrived as nitrate">.

cheers Darrel

Thanks for the welcome 🙂

I do have five Amano shrimp in the tank, along with six fish (danio's).

Isn't the only difference between TNC Lite and TNC Complete the nitrate levels? If so, would it likely be a nitrate related issue causing these holes in my leaves?

I had read that it could be a deficiency of potassium, does that sound a likely cause? I found that Seachem do a 'potassium supplement' bottle if that's the issue I'm having.
I'm just a bit cautious on what I add in the tank as don't want to end up creating other problems in the process.

 

[dw1305]

Hi all,

Thanks for the welcome

You are good, our aim is for every one to have a successful planted tank and if we <"can help you get there">? We will.

I do have five Amano shrimp in the tank

It maybe the <"Amano shrimp"> causing the damage, but plant health definitely looks compromised as well.

Isn't the only difference between TNC Lite and TNC Complete the nitrate levels? If so, would it likely be a nitrate related issue causing these holes in my leaves?

Yes, it has nitrate (NO3-) and phosphate (PO4---) as well. Nitrogen (N) is the nutrient plants need most of and <"they usually show a linear growth response"> to added nitrogen, if nitrogen was <"Liebig's limiting nutrient">.

Nitrogen (N), phosphorus (P) and potassium (K) are macronutrients that plants need most of and all of them are <"mobile within the plant">, so pale green older leaves are likely to indicate a deficiency of one or more of these.

You can get tap water values from your water supplier, they have an analytical lab. so their values will always be pretty accurate. In the SE of England some water companies are now using blended supplies to <"reduce levels of nitrate in tap water">.

I had read that it could be a deficiency of potassium, does that sound a likely cause? I found that Seachem do a 'potassium supplement' bottle if that's the issue I'm having.

It could be potassium, we really don't know, but you have been adding potassium in your "TNC lite" so my guess would be that it isn't. "Seachem Potassium" is fine to use, but it is an <"incredibly expensive way"> of adding potassium. <"Every K+ ion in solution is the same as every other one">, it doesn't know where it came from, there aren't any special <"ADA, JBL or Seachem ones">.

The other nutrient, that causes pale older leaves, and that is often in short supply in UK tap water is magnesium (Mg), which can be very easily added via <"Epsom Salts"> (MgSO4.7H2O).

Pale new leaves indicate a lack of <"one of the non-mobile plant nutrients">, and this is nearly always iron (Fe).

cheers Darrel

 

[ceg4048]

I had read that it could be a deficiency of potassium, does that sound a likely cause?

Hello,
Black spots and holes, if not a result of predation, is caused by poor CO2.
If this is a Co2 injected tank then review your CO2 technique. If this is a non-CO2 injected tank then the cause is related to excessive lighting - and this is the only variable that can be realistically adjusted in a non-CO2 injected tank.
A good trim will also help reduce the CO2 demand.

Cheers,

 

[dw1305]

Hi all,

Black spots and holes, if not a result of predation, is caused by poor CO2.

This is the major reason why I like a floating, or emergent, plant for the <"Duckweed Index">, it takes <"CO2 (and in nearly all circumstances light) out of the equation">. A floating plant has access to ~ 415 ppm atmospheric CO2 via <"stomata in the upper leaf surface">.

All you need to do is observe <"the leaf growth and colour (degree of green) of your floating plant">, if either of these are compromised it is very, very likely to be a <"nutrient issue">.

cheers Darrel

 

[misterbiscuit]

Thank you for the detailed responses.

I don't think it is the shrimp causing any damage (I was told Amano's don't eat plants?), or at least I haven't noticed them ever sitting on the plants and eating at them.

My tank is not a CO2 injected tank (I know nothing about doing that 😀).
My light is currently set to come on for 9 hours (3pm-midnight) each day, as I had read somewhere this is a good amount for a decent amount of plants. Is this too much light?

And currently with the TNC Lite fertilizer, I do 3'ish capfuls per week (after water change).
My tank is just under 60L and I do have quite a few plants. I've kept a list here:

Spoiler

Background:
Java fern (microsorium pteropus)
Amazon sword (echinodorus amazonicus)
Hygrophila Siamensis 53B
Bacopa amplexicaulis

Mid/foreground:
Moss balls
Water wisteria (hygrophila difformis)
Anubias Nana
Roseafolia mini (alternanthera)
Cryptocoryne parva
Cryptocoryne nevelli
Micranthemum micranthemoides
Nomaphila siamensis parvifolia
Micranthemum Monte Carlo

Floating:
Amazon frogbit

So I don't know if what I'm dosing is enough, or if there is a better product available for this amount?

 

[G H Nelson]

Hi
A full tank shot image would be helpful.
As Clive stated black holes are usually a Co2 issue....as your lights are on for a 9 hour period this is driving the plants to uptake Co2 and Fertilizers when these two are depleted this can cause issues!
If you don't have Co2 injection this can cause and show unhealthy growth problems such at stretching/holes/black marks/twisting/stunted growth/glassy leaves etc
Best if you reduce your lighting and add an All in One fertilizer with added Epsom Salt
You can always make your own fertilizers to save cash!
hoggie

 

[dw1305]

Hi all,

A full tank shot image would be helpful.

It would.

I was told Amano's don't eat plants?

Like many others, I have had Amano problems once they developed a taste for certain plants like Alternanthera reineckii. I initially stocked them at 1 amano per 10 litres as that was the ratio I read on the internet. However, amanos can triple in size from their store-bought size and become aggressive.

I've not kept them, but there ae quite a few threads on UKAPS about them <"eating Alternanthera etc">.

Best if you reduce your lighting....

I have low tech., nutrient depleted, tanks on a long day, but I use <"floating plants as a "net curtain">.

and add an All in One fertilizer with added Epsom Salt. You can always make your own fertilizers to save cash!

Good advice. Try a <"complete fertiliser"> and see what happens.

cheers Darrel

 

[erwin123]

When it comes to Cherry Shrimp vs Amanos as the cleanup crew, my preference now is for Cherry Shrimps. The main downside of Cherry Shrimps is that they are likely to be eaten by most fish so they are not compatible with many community tanks.

Otherwise, here are some photos of the cleaning abilities of Cherries. 😎

 

[Matti]

I had holes on my Hygrophila and in my case it was due to the lack of potassium.
Matti

 

[misterbiscuit]

Apologies for the late response.

As requested here is a full tank shot:


Admittedly I've gone a bit mad with many different species of plants. I got a bit addicted I suppose to adding them and seeing what plants looked/grew nicely.

I've now reduced my light down to 6 hours per day.
It's been suggested I switch to a 'complete' fertiliser. Is TNC Complete the recommended one to go for or is there a better option for my plant selection?

 

[G H Nelson]

Hi
Just use the Lite till the bottle is empty....if you do regular water changes you can continue to use the TNC Lite!
Best if you cut where the new growth starts on the stems and replant....discard the bottoms as the bottom halves are emersed growth.
hoggie