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Is Crepidomanes Fern a Good Plant for Blue Back Blue Eye?

Reviewed by Guidarium Editorial DeskUpdated May 2, 2026
Not Recommended

Crepidomanes Fern is not recommended for Blue Back Blue Eye. The issue is practical, not cosmetic: they are adapted to different water types.

Crepidomanes Fern

Crepidomanes auriculatum

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PlacementAttached to hardscape
LightLow
DifficultyAdvanced
Size15 × 20 cm

Blue Back Blue Eye

Pseudomugil cyanodorsalis

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TemperamentPeaceful
FamilyRainbowfish
Temp22–30°C
Water TypeBrackish Required

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

72/100

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

Water match

Limited overlap

One or more core water ranges does not overlap cleanly.

Plant pressure

Low

Blue Back Blue Eye is not flagged as unusually hard on this plant.

Layout value

Low cover

Crepidomanes Fern helps with good refuge for shrimp and good grazing surface.

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
Crepidomanes Fern20-26°C
Blue Back Blue Eye22-30°C

Overlap: 22-26°C.

pH
Crepidomanes Fern5.5-7.5
Blue Back Blue Eye7-8.5

Overlap: pH 7-7.5.

Hardness
Crepidomanes Fern2-10 dGH
Blue Back Blue Eye10-30 dGH

Overlap: 10-10 dGH.

Water and flow
Crepidomanes FernFreshwater Only, Moderate (Standard)
Blue Back Blue EyeBrackish Required, Moderate (Standard)

Flow expectations are close enough for one layout.

Space used
Crepidomanes FernAttached to hardscape, Foreground, and Midground
Blue Back Blue EyeTop (Surface) and Middle (Open Water)
Pressure signals
Crepidomanes FernModerate uproot resistance, Delicate leaves
Blue Back Blue EyePeaceful, Nano / Bite-sized (Predation Risk), Jumper (Lid Required), and Hyperactive / Fast Swimmer

Plant pressure: Low.

Planting value
Crepidomanes FernGood refuge for shrimp and Good grazing surface, No substrate required
Blue Back Blue EyeDriftwood (Digestion/Hiding) and Sand (Sifters)

Shared Tank Conditions

Crepidomanes Fern and Blue Back Blue Eye do not share a clean environmental window, so the pairing is already under pressure before behaviour is even considered.

Both do best with moderate flow, so circulation does not need to be split into competing zones.

Water type is a serious mismatch: Crepidomanes Fern is listed for freshwater, while Blue Back Blue Eye is listed for brackish water.

Fish Pressure and Plant Resilience

Blue Back Blue Eye does not put unusual pressure on this plant compared with harder fish-plant combinations.

Crepidomanes Fern has low cover density, moderate uproot resistance, and delicate leaves. It can also help with shrimp refuge and grazing surfaces.

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

The limiting issue is they are adapted to different water types.

Layout Fit

Crepidomanes Fern is a rhizome / epiphyte plant usually used attached to hardscape, foreground, and midground.

Blue Back Blue Eye is a rainbowfish, so the pairing works best when the planting style supports how that fish uses space and cover.

Crepidomanes Fern reaches about 15 cm tall by 20 cm wide and is usually attached / wedged to hardscape with no substrate required. 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 shrimp refuge and grazing surfaces. Place it where Blue Back Blue Eye 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: They are adapted to different water types.

Best Use Case

Crepidomanes Fern is usually the wrong plant for Blue Back Blue Eye 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 Crepidomanes Fern and Blue Back Blue Eye

Is Crepidomanes Fern a good plant for Blue Back Blue Eye?

Crepidomanes Fern is not recommended for Blue Back Blue Eye. The issue is practical, not cosmetic: they are adapted to different water types.

Can Blue Back Blue Eye damage Crepidomanes Fern?

They are adapted to different water types.

Do Crepidomanes Fern and Blue Back Blue Eye share the same water conditions?

No. The biggest issue is that their water conditions do not line up cleanly enough for a long-term planted setup.

What does Crepidomanes Fern add to a tank with Blue Back Blue Eye?

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?

They are adapted to different water types.

Editorial Review

Guidarium Editorial Desk

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

Last reviewed
May 2, 2026
Last updated
May 2, 2026
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