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Is Slender Hairgrass a Good Plant for San Juan Cory?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Not Recommended

Slender Hairgrass is not recommended for San Juan Cory. The issue is practical, not cosmetic: san Juan Cory is likely to uproot this plant while digging through the substrate.

Slender Hairgrass

Eleocharis acicularis

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PlacementForeground
LightModerate
DifficultyIntermediate
Size15 × 10 cm

San Juan Cory

Corydoras bilineatus

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TemperamentPeaceful
FamilyCatfish
Temp22–26°C
Water TypeFreshwater Only

Quick Decision

A plant can be technically compatible with a fish and still fail in the actual tank if the fish digs, chews, needs denser cover, or uses a different part of the layout.

Overall fit

58/100

The fish is likely to outgrow, uproot, or out-pressure the plant.

Water match

Workable overlap

Shared range: 22-26°C, pH 6-7.5, 4-12 dGH.

Plant pressure

High

San Juan Cory may chew, uproot, or stress this plant.

Layout value

High cover

Slender Hairgrass helps with provides surface cover, good refuge for shrimp, good grazing surface, and useful spawning site.

Plant and Fish Fit Notes

Use these signals to decide whether the plant is doing useful work for the fish, or whether it is only surviving beside it.

Temperature
Slender Hairgrass10-28°C
San Juan Cory22-26°C

Overlap: 22-26°C.

pH
Slender Hairgrass6-7.5
San Juan Cory6-7.5

Overlap: pH 6-7.5.

Hardness
Slender Hairgrass2-12 dGH
San Juan Cory4-18 dGH

Overlap: 4-12 dGH.

Water and flow
Slender HairgrassFreshwater Only, Moderate (Standard)
San Juan CoryFreshwater Only, Low (Still Water)

Flow expectations are close enough for one layout.

Space used
Slender HairgrassForeground, Carpeting, and Midground
San Juan CoryBottom (Substrate)
Pressure signals
Slender HairgrassLow uproot resistance, Delicate leaves
San Juan CoryPeaceful, Hyperactive / Fast Swimmer and Digger (Disturbs Substrate)

Plant pressure: High.

Planting value
Slender HairgrassProvides surface cover, Good refuge for shrimp, Good grazing surface, and Useful spawning site, Nutrient-rich substrate preferred
San Juan CorySand (Sifters) and Smooth Gravel (Sensitive Barbels)

Shared Tank Conditions

Slender Hairgrass fits inside the water range normally used for San Juan Cory. The shared window is about 22 to 26 °C, pH 6 to 7.5, and 4 to 12 dGH, which gives you enough room to aim for stable middle-ground conditions.

Their flow expectations are close enough to combine: Slender Hairgrass prefers moderate flow, while San Juan Cory prefers gentle, low-flow water.

Both are suited to freshwater, so salinity does not add an extra planning problem.

Fish Pressure and Plant Resilience

San Juan Cory puts heavy pressure on plants, so this species is likely to be chewed, uprooted, or stressed in day-to-day use.

Slender Hairgrass has high cover density, low uproot resistance, and delicate leaves. It can also help with surface cover, shrimp refuge, grazing surfaces, and spawning sites.

Its structure adds useful refuge value beyond the normal visual role of the plant.

The limiting issue is san Juan Cory is likely to uproot this plant while digging through the substrate.

Layout Fit

Slender Hairgrass is a stolon / runner plant usually used foreground, carpeting, and midground.

San Juan Cory is a catfish, so the pairing works best when the planting style supports how that fish uses space and cover.

Slender Hairgrass reaches about 15 cm tall by 10 cm wide and is usually rooted in substrate with nutrient-rich substrate preferred. That makes placement and anchoring more important than simply adding a larger bunch of stems or leaves.

In this pairing, the useful plant values are surface cover, shrimp refuge, grazing surfaces, and spawning sites. Place it where San Juan Cory can actually use that structure instead of hiding the plant where it cannot do much.

Practical Recommendation

For most keepers, a tougher or better-matched plant is the smarter choice. If you still try it, test with a small amount first and be ready to move the plant before it is badly damaged.

The decision should center on this signal: San Juan Cory is likely to uproot this plant while digging through the substrate.

Best Use Case

Slender Hairgrass is usually the wrong plant for San Juan Cory if your goal is a stable display tank. The issue is rarely one dramatic failure on day one; it is the steady mismatch between what the fish does in the scape and what the plant needs to stay attractive long term.

Frequently Asked Questions About Slender Hairgrass and San Juan Cory

Is Slender Hairgrass a good plant for San Juan Cory?

Slender Hairgrass is not recommended for San Juan Cory. The issue is practical, not cosmetic: san Juan Cory is likely to uproot this plant while digging through the substrate.

Can San Juan Cory damage Slender Hairgrass?

San Juan Cory is likely to uproot this plant while digging through the substrate.

Do Slender Hairgrass and San Juan Cory share the same water conditions?

Slender Hairgrass and San Juan Cory share a workable water window around 22 to 26 °C, pH 6 to 7.5, and 4 to 12 dGH. Keep the tank near the middle of that overlap for the best long-term result.

What does Slender Hairgrass add to a tank with San Juan Cory?

Its structure adds useful refuge value beyond the normal visual role of the plant.

What is the main risk in this plant and fish pairing?

San Juan Cory is likely to uproot this plant while digging through the substrate.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 11, 2026
Last updated
May 11, 2026
Issues or corrections?
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