diff --git a/Cargo.toml b/Cargo.toml
index 0026d5d..b920db8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bio-streams"
-version = "0.4.0"
+version = "0.5.0"
 edition = "2021"
 authors = ["jeff-k <jeff_k@fastmail.com>"]
 description = "Streaming bioinformatics data types"
@@ -13,13 +13,11 @@ readme = "README.md"
 futures = "0.3"
 futures-test = "0.3"
 bio-seq = "0.13"
-#bio-seq = { path = "../bio-seq/bio-seq" }
 
 [dev-dependencies]
 flate2 = "1"
 clap = { version="4", features=["derive"] }
 bio-seq = "0.13"
-#bio-seq = { path = "../bio-seq/bio-seq" }
 
 [[example]]
 name = "fqcheck"
diff --git a/src/fasta.rs b/src/fasta.rs
index efe0597..eea759d 100644
--- a/src/fasta.rs
+++ b/src/fasta.rs
@@ -8,15 +8,7 @@ use futures::stream::Stream;
 
 use bio_seq::prelude::*;
 
-use crate::Record;
-
-#[derive(Debug, PartialEq)]
-pub enum FastaError {
-    InvalidId(String),
-    TruncatedRecord,
-    InvalidSequence,
-    FileError,
-}
+use crate::{FastxError, Reader, Record};
 
 pub struct Fasta<R: BufRead, T = Seq<Dna>>
 where
@@ -50,7 +42,7 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fasta<R, T
         }
     }
 
-    fn parse_record(&mut self) -> Option<Result<Record<T>, FastaError>> {
+    fn parse_record(&mut self) -> Option<Result<Record<T>, FastxError>> {
         let reader = Pin::get_mut(self.reader.as_mut());
 
         let mut seq_buf: Vec<u8> = Vec::new();
@@ -67,13 +59,13 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fasta<R, T
                     //                    let end = end_pos(&self.line_buf);
                     Vec::from(&self.line_buf[1..end_pos(&self.line_buf)])
                 } else {
-                    return Some(Err(FastaError::InvalidId(
+                    return Some(Err(FastxError::InvalidId(
                         String::from_utf8_lossy(&self.line_buf).into_owned(),
                     )));
                 }
             } else {
                 // premature end of fasta?
-                return Some(Err(FastaError::TruncatedRecord));
+                return Some(Err(FastxError::TruncatedRecord));
             }
         } else {
             self.field_buf.take().unwrap()
@@ -100,7 +92,7 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fasta<R, T
         let seq = match T::try_from(&seq_buf) {
             Ok(s) => s,
             Err(_) => {
-                return Some(Err(FastaError::InvalidSequence));
+                return Some(Err(FastxError::InvalidSequence("TODO".to_string())));
             }
         };
         Some(Ok(Record {
@@ -111,8 +103,8 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fasta<R, T
     }
 }
 
-impl<R: BufRead + Unpin, A: Codec> Iterator for Fasta<R, Seq<A>> {
-    type Item = Result<Record<Seq<A>>, FastaError>;
+impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Iterator for Fasta<R, T> {
+    type Item = Result<Record<T>, FastxError>;
 
     fn next(&mut self) -> Option<Self::Item> {
         self.parse_record()
@@ -120,7 +112,7 @@ impl<R: BufRead + Unpin, A: Codec> Iterator for Fasta<R, Seq<A>> {
 }
 
 impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Stream for Fasta<R, T> {
-    type Item = Result<Record<T>, FastaError>;
+    type Item = Result<Record<T>, FastxError>;
 
     fn poll_next(
         self: Pin<&mut Self>,
@@ -132,6 +124,8 @@ impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Stream for Fasta<
     }
 }
 
+impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Reader<T> for Fasta<R, T> {}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/fastq.rs b/src/fastq.rs
index d145f77..6d387bf 100644
--- a/src/fastq.rs
+++ b/src/fastq.rs
@@ -1,49 +1,15 @@
 use core::marker::{PhantomData, Unpin};
 
-use std::fmt;
 use std::io::BufRead;
 use std::pin::Pin;
 use std::task::{Context, Poll};
-//use std::error;
 
 use futures::stream::Stream;
 
 use bio_seq::prelude::*;
 
 use crate::record::Phred;
-use crate::Record;
-
-#[derive(Debug, PartialEq)]
-pub enum FastqError {
-    InvalidSeparationLine,
-    InvalidId(String),
-    TruncatedRecord,
-    InvalidSequence(String),
-    InvalidQuality,
-    FileError,
-}
-
-impl fmt::Display for FastqError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            FastqError::InvalidSeparationLine => write!(f, "Invalid separation character"),
-            FastqError::InvalidId(id) => write!(f, "Invalid id: {id}"),
-            FastqError::TruncatedRecord => write!(f, "Truncated record"),
-            FastqError::InvalidSequence(seq) => write!(f, "Invalid sequence: {seq}"),
-            FastqError::InvalidQuality => write!(f, "Invalid quailty string"),
-            FastqError::FileError => write!(f, "File error"),
-        }
-    }
-}
-
-/*
-impl error::Error for FastqError {
-    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
-        match self {
-        }
-    }
-}
-    */
+use crate::{FastxError, Reader, Record};
 
 pub struct Fastq<R: BufRead, T = Seq<Dna>>
 where
@@ -71,7 +37,7 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fastq<R, T
         }
     }
 
-    fn parse_record(&mut self) -> Option<Result<Record<T>, FastqError>> {
+    fn parse_record(&mut self) -> Option<Result<Record<T>, FastxError>> {
         let mut quality = Vec::<Phred>::new();
         let reader = Pin::get_mut(self.reader.as_mut());
 
@@ -81,7 +47,7 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fastq<R, T
         self.qual_buf.clear();
 
         if reader.read_until(b'\n', &mut self.id_buf).is_err() {
-            return Some(Err(FastqError::FileError));
+            return Some(Err(FastxError::FileError));
         }
         if self.id_buf.is_empty() {
             // This is the only condition where an empty reader means
@@ -90,45 +56,45 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fastq<R, T
         }
         // The id line must begin with '@'
         if self.id_buf[0] != b'@' {
-            return Some(Err(FastqError::InvalidId(
+            return Some(Err(FastxError::InvalidId(
                 String::from_utf8_lossy(&self.id_buf).into_owned(),
             )));
         }
 
         if reader.read_until(b'\n', &mut self.seq_buf).is_err() {
-            return Some(Err(FastqError::FileError));
+            return Some(Err(FastxError::FileError));
         }
         if self.seq_buf.is_empty() {
-            return Some(Err(FastqError::TruncatedRecord));
+            return Some(Err(FastxError::TruncatedRecord));
         }
 
         if reader.read_until(b'\n', &mut self.sep_buf).is_err() {
-            return Some(Err(FastqError::FileError));
+            return Some(Err(FastxError::FileError));
         }
         if self.sep_buf.is_empty() {
-            return Some(Err(FastqError::TruncatedRecord));
+            return Some(Err(FastxError::TruncatedRecord));
         }
 
         // Detect whether the '+' separation line is valid
         if self.sep_buf.len() != 2 || self.sep_buf[0] != b'+' {
-            return Some(Err(FastqError::InvalidSeparationLine));
+            return Some(Err(FastxError::InvalidSeparationLine));
         }
         if reader.read_until(b'\n', &mut self.qual_buf).is_err() {
-            return Some(Err(FastqError::FileError));
+            return Some(Err(FastxError::FileError));
         }
         if self.qual_buf.is_empty() {
-            return Some(Err(FastqError::TruncatedRecord));
+            return Some(Err(FastxError::TruncatedRecord));
         }
 
         // Parse the contents of the sequence and quality lines
         if self.qual_buf.len() != self.seq_buf.len() {
-            return Some(Err(FastqError::InvalidQuality));
+            return Some(Err(FastxError::InvalidQuality));
         }
 
         let seq = match T::try_from(&self.seq_buf[..self.seq_buf.len() - 1]) {
             Ok(parsed_seq) => parsed_seq,
             Err(_) => {
-                return Some(Err(FastqError::InvalidSequence(
+                return Some(Err(FastxError::InvalidSequence(
                     String::from_utf8_lossy(&self.seq_buf).into_owned(),
                 )))
             }
@@ -148,8 +114,8 @@ impl<R: BufRead + Into<Box<R>> + Unpin, T: for<'a> TryFrom<&'a [u8]>> Fastq<R, T
     }
 }
 
-impl<R: BufRead + Unpin, A: Codec> Iterator for Fastq<R, Seq<A>> {
-    type Item = Result<Record<Seq<A>>, FastqError>;
+impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Iterator for Fastq<R, T> {
+    type Item = Result<Record<T>, FastxError>;
 
     fn next(&mut self) -> Option<Self::Item> {
         self.parse_record()
@@ -157,7 +123,7 @@ impl<R: BufRead + Unpin, A: Codec> Iterator for Fastq<R, Seq<A>> {
 }
 
 impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Stream for Fastq<R, T> {
-    type Item = Result<Record<T>, FastqError>;
+    type Item = Result<Record<T>, FastxError>;
 
     fn poll_next(
         self: Pin<&mut Self>,
@@ -169,6 +135,8 @@ impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Stream for Fastq<
     }
 }
 
+impl<R: BufRead + Unpin, T: Unpin + for<'a> TryFrom<&'a [u8]>> Reader<T> for Fastq<R, T> {}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/record.rs b/src/record.rs
index dbe069c..7bee696 100644
--- a/src/record.rs
+++ b/src/record.rs
@@ -1,5 +1,8 @@
 use core::fmt;
 use core::str;
+use futures::Stream;
+
+use crate::FastxError;
 
 #[derive(Debug, PartialEq, Copy, Clone)]
 pub struct Phred(u8);
@@ -51,3 +54,8 @@ impl<'a, T: for<'b> TryFrom<&'b [u8]>> Record<T> {
         unimplemented!()
     }
 }
+
+pub trait Reader<T: for<'a> TryFrom<&'a [u8]>>:
+    Iterator<Item = Result<Record<T>, FastxError>> + Stream<Item = Result<Record<T>, FastxError>>
+{
+}